Fermentation

17 pages, 4018 KiB

Open AccessArticle

Isolation and Identification of Novel Non-Dairy Starter Culture Candidates from Plant Matrix Using Backslopping Propagation

by Maret Andreson, Jekaterina Kazantseva, Aili Kallastu, Taaniel Jakobson, Inga Sarand and Mary-Liis Kütt

Fermentation 2024, 10(12), 663; https://doi.org/10.3390/fermentation10120663 - 23 Dec 2024

Viewed by 865

Abstract

The majority of non-dairy starter cultures on the market are originally isolated from milk and therefore do not provide the most optimal fermentation for plant matrices. Developing plant-derived starter cultures is essential for creating high-quality, tasty dairy alternatives. This study aims to isolate [...] Read more.

The majority of non-dairy starter cultures on the market are originally isolated from milk and therefore do not provide the most optimal fermentation for plant matrices. Developing plant-derived starter cultures is essential for creating high-quality, tasty dairy alternatives. This study aims to isolate and characterize bacterial strains with the potential to be used as non-dairy starters from plant sources via backslopping evolution. A natural consortium of macerated plants was inoculated into two oat and two pea commercial drinks and backslopped for seventeen cycles to evolve the bacterial consortium at 25 °C, 34 °C, and 42 °C. The results showed that the initial natural consortium contained less than 1% lactic acid bacteria, and after the seventeenth cycle, lactic acid bacteria dominated in all investigated consortia. Oat Od1-25 and Od2-42 and pea Pd1-34 and Pd1-42 samples were selected for strain isolation based on amplicon-based metagenetic analysis of 16S rRNA gene sequencing and sensory properties. The strain isolation was performed using an out-plating technique, and colonies were identified by MALDI-TOF mass spectrometry. Altogether, eleven lactic acid bacteria species of plant origin were obtained. The strains belonged to the Leuconostoc, Enterococcus, Lactobacillus, and Lactococcus genera. Full article

(This article belongs to the Special Issue Microbiota and Metabolite Changes in Fermented Foods)

► Show Figures

Figure 1

23 pages, 3717 KiB

Open AccessArticle

Influence of Yeast Interactions on the Fermentation Process and Aroma Production in Synthetic Cocoa Pulp vs. Real Mucilage Media

by Lydie Besançon, Da Lorn, Christelle Kouamé, Joël Grabulos, Marc Lebrun, Angélique Fontana, Sabine Schorr-Galindo, Renaud Boulanger, Caroline Strub and Alexandre Colas de la Noue

Fermentation 2024, 10(12), 662; https://doi.org/10.3390/fermentation10120662 - 21 Dec 2024

Viewed by 775

Abstract

Cocoa fermentation plays a key role in defining chocolate’s flavor, with yeasts being central to this process. This study aimed to explore intraspecific genetic diversity of major indigenous yeasts (i.e., Saccharomyces cerevisiae and Pichia kudriavzevii), and their potential interaction in the cocoa [...] Read more.

Cocoa fermentation plays a key role in defining chocolate’s flavor, with yeasts being central to this process. This study aimed to explore intraspecific genetic diversity of major indigenous yeasts (i.e., Saccharomyces cerevisiae and Pichia kudriavzevii), and their potential interaction in the cocoa pulp environment. Their metabolic intraspecific diversity was characterized in synthetic cocoa pulp medium. Then, Saccharomyces cerevisiae, Pichia kudriavzevii, and other strains were introduced to each other to evaluate their potential negative interaction. Interesting strain associations were selected to further explore their interaction in synthetic cocoa pulp medium as well as real fresh cocoa pulp. From a fermentation campaign in Ivory Coast, a set of Saccharomyces (S.) cerevisiae and Pichia (P.) kudriavzevii strains were isolated from batches classified according to their chocolate quality (i.e., standard, intermediate, or premium chocolate). Less abundant species (i.e., Torulaspora franciscae, Kluyveromyces marxianus) were also isolated and tested for their potential negative interactions with S. cerevisiae and P. kudriavzevii. A set of strains were selected and cultured in single and in co-culture in a minimal cocoa pulp synthetic medium and in fresh cocoa pulp to highlight potential positive and/or negative interactions regarding fermentative aroma profile (i.e., higher alcohols, acetate esters, medium-chain fatty acids, and ethyl esters). The results highlighted the dominance of S. cerevisiae in fermentation kinetics and medium- to long-chain ester production, contrasted with P. kudriavzevii’s efficiency in short-chain ester synthesis. Intraspecific aroma profile variations can be pointed out. The co-cultures of P. kudriavzevii and S. cerevisiae strains isolated from the premium chocolate batch had a positive impact on the fermented pulp aroma profile. Negative interactions were observed with Torulaspora franciscae, which eliminated P. kudriavzevii’s aroma expression. Finally, the comparison of the data obtained for the minimal cocoa pulp synthetic medium compared to the cocoa pulp allowed us to draw conclusions about the use of synthetic media for studying cocoa fermentation. These findings emphasize the complex microbial interactions in cocoa fermentation that could shape future cocoa bean aroma. Full article

(This article belongs to the Special Issue Development and Application of Starter Cultures, 2nd Edition)

► Show Figures

Figure 1

Figure 1
Cluster analysis showing the intraspecies relationship of the isolates of the 19 strains of S. cerevisiae (a) and the 19 strains of P. kudriavzevii (b) by (GTG)5-rep-PCR fingerprinting. The strains selected for the next steps of analysis are indicated by an *. Solid-line frames (―) indicate the premium-quality chocolate batch, dotted-line frames (- -) indicate the intermediate-quality batch, and unframed isolates indicate the standard-quality batch. (c) Maximum CO2 release rate (g/L.h−1) distribution between the 19 strains of S. cerevisiae and the 19 strains of P. kudriavzevii in glucose-rich YPD medium in static conditions at 30 °C for 7 days. Full article ">Figure 2
Illustration of the inhibitory effect observed during killer assay between (a,b) S. cerevisiae S56 and K. marxianus N22, and (c,d) P.kudriavzevii P66 and T. franciscea N5. YPD medium acidified with citrate phosphate buffer at pH 3.7 (b,d) and pH 4.5 (a,c) with methylene blue. A similar behaviour (c,d) was observed between N5 and all P. kudriavzevii strains. For S. cerevisiae, only strains S56, S59, S60, and S77 showed negative interactions with N22. No other interactions were observed between all the strains. Full article ">Figure 3
Heatmap (z-scores, with blue indicating lower values and red indicating higher values) and boxplot summary (z-scores) of the aroma profile of minimal cocoa pulp synthetic medium (MPS) fermented by single S. cerevisiae (S), P. kudriavzevii (P), and non-S. cerevisiae (N) strains after 5 days of fermentation (30 °C). Clustering was performed using the Euclidean distance metric for both yeast strains (columns) and aromatic compounds (row), grouping similar profiles together. Abbreviations: S77, single culture of S. cerevisiae S77; P76, single culture of P. kudriavzevii P76; N22, single culture of K. marxianus N22. Solid-line frames (―) indicate the premium-quality chocolate batch, dotted-line frames (- -) indicate the intermediate-quality batch, and unframed match indicate the standard-quality batch. Full article ">Figure 4
Radar chart representation of standardized aroma z-scores for individual yeast strains and their respective co-cultures in the MPS medium after 5 days of fermentation (30 °C). Each line represents the aroma profile of a particular yeast strain or co-culture (P36, S4, S35, S77, N5, N22, S77+N22, N5+P36, S35+P36, and P36+S4) based on the distinct aroma profiles of (a–d) P. kudriavzevii and (e–h) S. cerevisiae. The strains selected illustrate a range of fermentation and aroma production capabilities: P36, the top P. kudriavzevii strain aroma producer from the premium batch; S35, highly active S. cerevisiae strain with strong aroma potential from the premium batch; S4, the control with intermediate fermentation performance and low aroma potential; N5 and N22, non-S. cerevisiae strains with inhibitory impact; and S77, a S. cerevisiae strain known for its interaction with N22. Full article ">Figure 5
Fermentation kinetics and yeast viability during cocoa pulp fermentation (30 °C): (a) total yeast biomass for S. cerevisiae (S35), P. kudriavzevii (P36), and T. franciscae (N5) in single cultures; (b) yeast biomass distribution in co-cultures (S35+P36); (c) yeast biomass distribution in co-cultures (N5+P36); (d–f) sugar consumption (sucrose, glucose, and fructose); (g) CO2 release; (h) ethanol production throughout fermentation. Full article ">Figure 6
Principal component analysis (PCA) based on the main volatile compounds (esters and higher alcohols) produced by single and co-cultures of S. cerevisiae S35, P. kudriavzevii P36, and non-S. cerevisiae N5 in the cocoa pulp medium at different times of fermentation, from 0 h to 120 h. (a) Loading plot and (b) score plot showing the influence of the strains (colors) and the fermentation time in hours (shapes). Single and co-culture strains and species details are explained in the legend of the figure. Abbreviations: S35, single culture of S. cerevisiae S35; P36, single culture of P. kudriavzevii P36; N5, single culture of T. franciscae N5; S35+P36, co-culture of S35 and P36; N5+P36, co-culture of N5 and P36. Full article ">

13 pages, 4032 KiB

Open AccessArticle

Biofilm-Based Immobilization Fermentation for Continuous hEGF Production in Saccharomyces cerevisiae

by Kaiqi Zhi, Zhiguo An, Mingyang Zhang, Kehan Liu, Yafan Cai, Zhenyu Wang, Di Zhang, Jinle Liu, Zhi Wang, Chenjie Zhu, Dong Liu, Sheng Yang and Hanjie Ying

Fermentation 2024, 10(12), 661; https://doi.org/10.3390/fermentation10120661 - 21 Dec 2024

Viewed by 826

Abstract

Biofilms can enhance industrial fermentation efficiency by increasing cell density, stability, and metabolic activity and have been successfully applied to the continuous production of many small-molecule chemicals. However, the continuous production of proteins by biofilms has been less studied. This study used secretory [...] Read more.

Biofilms can enhance industrial fermentation efficiency by increasing cell density, stability, and metabolic activity and have been successfully applied to the continuous production of many small-molecule chemicals. However, the continuous production of proteins by biofilms has been less studied. This study used secretory human epidermal growth factor (hEGF) as a representative product to evaluate and optimize biofilm-based continuous protein production. First, by deleting the protease and overexpressing eight key genes involved in protein secretion in Saccharomyces cerevisiae, the yield of hEGF was improved by 82.6% from 77.4 to 141.3 mg/L in shake flasks. Subsequently, the flocculation genes FLO11 and ALS3 were introduced to facilitate the establishment of a biofilm-based continuous immobilization fermentation model. The optimal strain SIC-ALS3-PDI1 produced 583.8 mg/L of hEGF, with a productivity of 4.9 mg/L/h during traditional free-cell fermentation, while it produced an average of 300.0 mg/L of hEGF in 10 continuous batches of biofilm-based fermentation, with a productivity of 6.3 mg/L/h. Although the hEGF production in biofilms was lower than that in free-cell fermentation, biofilm fermentation demonstrated greater productivity, with the advantage of not requiring seed culture for each batch of fermentation. This study provided a valuable reference for the biofilm-based production of other peptides. Full article

(This article belongs to the Special Issue Research on Microbial Protein Synthesis: 2nd Edition)

► Show Figures

Figure 1

Figure 1
A schematic diagram of hEGF production through biofilm-based continuous immobilization fermentation. This study developed and optimized an hEGF expression system in S. cerevisiae. Biofilm-forming genes have been introduced to create biofilm strains that enable cell adsorption on carriers. A biofilm-based continuous immobilization fermentation system was established, which can produce hEGF continuously. Full article ">Figure 2
Engineering protein secretory pathway to enhance hEGF production. (a) The schematic diagram of hEGF expression in SIC strain. (b) The results of protease-deficient strains in shake flasks. (c) The results of overexpressing strains in shake flasks. Full article ">Figure 3
The characterization of biofilm strains. (a) Agarose plate invasion experiment. (b) The biofilm strains were cultured in a shaking flask for 72 h. (c) The effect of biofilm-forming genes on the performance of the strain. (d) The results of OD600 for biofilm strains cultured in shake flasks for 72 h in both free and immobilization phases. (e) hEGF yield cultured in shake flasks for 72 h. Full article ">Figure 4
The exploration of fermentation parameters’ pH and initial glucose concentration. (a) The relationship between pH and hEGF production. (b) The effects of different initial glucose concentrations on hEGF production. Full article ">Figure 5
The exploration of a single-batch fermentation period. (a) The results of OD600 in shake flasks. (b) The results of hEGF yield in shake flasks. Full article ">Figure 6
The results of fermentation in the bioreactor. (a) The results of the biofilm-based immobilization fermentation for SIC-FLO11-PDI1 strain. (b) The results of free-cell fermentation for SIC-FLO11-PDI1 strain. (c) The results of the biofilm-based immobilization fermentation for SIC-ALS3-PDI1 strain. (d) The results of free-cell fermentation for SIC-ALS3-PDI1 strain. Full article ">Figure 7
The results of unengineered SIC strains in different fermentation systems: (a) biofilm fermentation systems; (b) free-cell fermentation systems. Full article ">

14 pages, 2128 KiB

Open AccessArticle

Plant-Scale Biogas Production Based on Integrating of CEEMDAN Decomposition with PSO Optimized Multilayer Perceptron Neural Network

by Dean Kong, Lijie Chu, Ping Yang, Yujing Guan, Hao Xu, Jie Chen, Yange Yu, Xiaochuan Yan, Bingfeng Liu, Guangli Cao and Xihai Zhang

Fermentation 2024, 10(12), 660; https://doi.org/10.3390/fermentation10120660 - 20 Dec 2024

Viewed by 560

Abstract

Accurate and dependable forecasting of biogas production is vital for optimizing process parameters and maintaining stable operation in large-scale anaerobic digestion projects. In this study, a novel hybrid approach (CEE-PMLP) integrating complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and a multilayer [...] Read more.

Accurate and dependable forecasting of biogas production is vital for optimizing process parameters and maintaining stable operation in large-scale anaerobic digestion projects. In this study, a novel hybrid approach (CEE-PMLP) integrating complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and a multilayer perceptron (MLP) neural network optimized by particle swarm optimization (PSO) were proposed for predicting biogas production in large-scale anaerobic digesters (ADs). The methodology involves extracting Intrinsic Mode Function (IMF) components using CEEMDAN and subsequently employing MLP optimized by particle swarm optimization (PSO) to predict each component. The performance of the models was evaluated using root mean square error (RMSE), mean squared error (MSE), mean absolute error (MAE), and fitting determination coefficient (R²). The findings revealed that the prediction errors of the proposed CEE-PMLP model were consistently lower than those of other comparative models. Notably, the model achieved the highest R² value of 98%, indicating an exceptionally high accuracy in prediction. The validation experiment confirmed the high accuracy of the CEE-PMLP model, further demonstrating its superiority in biogas production prediction. Full article

(This article belongs to the Section Fermentation Process Design)

► Show Figures

Figure 1

16 pages, 4690 KiB

Open AccessArticle

Immobilization, Characterization and Application of a Xylose Isomerase Biocatalyst for Xylose Fermentation in Biorefineries

by Márcio D. N. Ramos, Juliana P. Sandri, Willian Kopp, Raquel L. C. Giordano and Thais S. Milessi

Fermentation 2024, 10(12), 659; https://doi.org/10.3390/fermentation10120659 - 20 Dec 2024

Viewed by 673

Abstract

A biocatalyst has been developed for application in the simultaneous isomerization and fermentation (SIF) of xylose, which could enable operation in repeated batches and the use of xylose from biomass hemicellulose for the production of second-generation (2G) ethanol. To this end, the enzyme [...] Read more.

A biocatalyst has been developed for application in the simultaneous isomerization and fermentation (SIF) of xylose, which could enable operation in repeated batches and the use of xylose from biomass hemicellulose for the production of second-generation (2G) ethanol. To this end, the enzyme xylose isomerase (XI) was immobilized on eleven different supports (based on chitosan, modified silica, agarose and magnetic supports) to obtain a derivative that is stable under process conditions and easy to recover from the fermented medium for future industrial application in biorefineries. Immobilization was performed with 5 mg/g_support, with a support-to-suspension ratio of 1:20. Phosphate (pH 7.0) and carbonate–bicarbonate (pH 10.05) buffer were used for uni-point and multi-point immobilization, respectively. Among the immobilized enzymes, the magnetic microparticle Captura N exhibited the best immobilization parameters (67% recovered activity and half-life of 10 h at 80 °C), in addition to its magnetic properties, which facilitates purification. The SIF of crude sugarcane straw acid hydrolysate was carried out in repeated batches using XI-chitosan and XI-Captura N. Although economically promising, chitosan-based supports did not enhance enzyme stability. Therefore, magnetic microparticles are a promising option as XI immobilization supports for biorefinery applications. Full article

(This article belongs to the Special Issue Technological Advances in Lignocellulosic Biomass Conversion to Bioenergy)

► Show Figures

Figure 1

Figure 1
(A) Xylose isomerase from Streptomyces rubiginosus; (B) structure of xylose isomerase with lysine residues in blue. Figures created in PyMOL 2.6 software with the 1load structure of the Protein Data Bank in Europe [<a href="#B17-fermentation-10-00659" class="html-bibr">17</a>]. Full article ">Figure 2
Immobilization kinetics of XI (5 mg/gsupport) on different supports: (A) chitosan-glutaraldehyde and chitosan-glutaraldehyde modified with 5% and 10% S. cerevisiae; (B) modified silicas; (C) magnetic silicas; and (D) multi-point supports. Immobilization conditions (A–C): 100 mmol/L sodium phosphate buffer pH 7.0 at room temperature. Immobilization conditions (D): 50 mmol/L carbonate–bicarbonate pH 10.05 at room temperature. Full article ">Figure 3
Scheme of the structure of the modified silica (Purifica) and magnetic silica (Captura) used in this study [<a href="#B48-fermentation-10-00659" class="html-bibr">48</a>]. Full article ">Figure 4
Inactivation profile of free and immobilized XI at 80 °C in a 50 mmol/L Tris-HCl buffer pH 7. (A) XI immobilized on chitosan-based supports, (B) XI immobilized on modified silicas, (C) XI immobilized on magnetic microparticles. Full article ">Figure 5
Residual activity of free and immobilized XI at 35 °C in SIF medium containing KH2PO4 (5 g/L), MgSO4 (2 g/L), CoCl2.6H2O (0.1 g/L) and urea (1.5 g/L) at pH 5.2 in the absence and presence of ethanol (EtOH, 70 g/L). Full article ">Figure 6
Follow-up of the SIF processes (35 °C, pH 5.2) of crude sugarcane straw hydrolysate performed in repeated batches and details of the mini-reactors used: (A,C) XI-chitosan and (B,D) XI-Captura-N with a magnet holding the immobilized enzymes. Full article ">

12 pages, 1161 KiB

Open AccessArticle

Characteristics of Solid Fuel from Carbonized Surface Pellets Using Food Waste Digestion Sludge and Unused Forest Biomass: A Case Study in South Korea

by Kwang-Ho Ahn, Ye-Eun Lee, Yoonah Jeong, Jinhong Jung and I-Tae Kim

Fermentation 2024, 10(12), 658; https://doi.org/10.3390/fermentation10120658 - 19 Dec 2024

Viewed by 771

Abstract

The promulgation of the Biogas Act in South Korea has increased the number of organic waste treatment facilities and the amount of food waste digestion sludge (FWDS), a byproduct of the biogas process. FWDS recovery involves various challenges, which leads to the accumulation [...] Read more.

The promulgation of the Biogas Act in South Korea has increased the number of organic waste treatment facilities and the amount of food waste digestion sludge (FWDS), a byproduct of the biogas process. FWDS recovery involves various challenges, which leads to the accumulation or improper disposal of sludge. Hence, FWDS needs to be treated in environmentally sound and safe ways. In this study, anaerobic digestion sludges were mixed with unused forest biomass to produce fuel. The results showed that pellets produced via mixing of FWDS with unused forest biomass had improved durability, bulk density, and fine particle performance compared to surface-carbonized wood pellets. Carbonized pellets manufactured with 30% FWDS had a moisture content of 11.746% and met all biosolid waste fuel (SRF) standards, except for moisture content. Carbonized pellets prepared with 15% FWDS met the L2 wood pellet standards for ash content (less than 3.0%) and bulk density (greater than 550 kg/m³), as well as all other standard values in both the industrial wood pellet quality standards and bio-SRF criteria. This study confirmed the potential and suitability of digestion sludge and unused forest biomass for fuel utilization by addressing their respective limitations. Full article

(This article belongs to the Special Issue Anaerobic Digestion: Waste to Energy: 2nd Edition)

► Show Figures

Figure 1

15 pages, 1187 KiB

Open AccessArticle

Enhancing Flavor Complexity in Craft Beer: Sequential Inoculation with Indigenous Non-Saccharomyces and Commercial Saccharomyces Yeasts

by María Victoria Mestre Furlani, Mercedes Fabiana Vargas Perucca, Diego Bernardo Petrignani, Silvia Cristina Vergara, María José Leiva-Alaniz, Yolanda Paola Maturano, Fabio Vazquez and Eduardo Dellacassa

Fermentation 2024, 10(12), 657; https://doi.org/10.3390/fermentation10120657 - 19 Dec 2024

Viewed by 685

Abstract

The pursuit of unique flavors in craft beer has led to the exploration of non-Saccharomyces (NS) yeasts. While Saccharomyces species dominate beer fermentation, NS yeasts offer flavor diversification. However, their lower fermentation efficiency and ethanol sensitivity limit their use. This study evaluated [...] Read more.

The pursuit of unique flavors in craft beer has led to the exploration of non-Saccharomyces (NS) yeasts. While Saccharomyces species dominate beer fermentation, NS yeasts offer flavor diversification. However, their lower fermentation efficiency and ethanol sensitivity limit their use. This study evaluated 50 NS yeast strains from Argentina’s Cuyo wine region. Torulaspora delbrueckii was selected for sequential fermentations with Saccharomyces cerevisiae due to its promising fermentative and physiological characteristics. Sequential inoculation resulted in a significant increase in fruity and spicy aromas, particularly esters like isoamyl acetate, ethyl hexanoate, and ethyl octanoate, as well as terpenes like limonene and linalool. Sensory analysis revealed that beers produced with T. delbrueckii were characterized by a more complex aroma profile, with significant increases in fruity, floral, and herbaceous notes. Additionally, the sequential fermentation strategy resulted in a higher apparent attenuation compared to pure T. delbrueckii fermentation, indicating improved sugar utilization. These findings highlight the potential of NS yeasts to enhance beer sensory characteristics. Combining NS yeasts with traditional Saccharomyces strains creates beers with distinctive flavors, expanding brewing possibilities. Sequential inoculation strategies offer a viable approach to harnessing the benefits of NS yeasts while ensuring fermentation. This research demonstrates the potential of NS yeasts to enrich the sensory experience of drinking craft beer, paving the way for further innovation in the brewing industry. Full article

(This article belongs to the Special Issue New Insights into the Biodiversity and Industrial Applications of Saccharomyces cerevisiae, 2nd Edition)

► Show Figures

Figure 1

19 pages, 11809 KiB

Open AccessArticle

Synergistic Promotion of Direct Interspecies Electron Transfer by Biochar and Fe₃O₄ Nanoparticles to Enhance Methanogenesis in Anaerobic Digestion of Vegetable Waste

by Hongruo Ma, Long Chen, Wei Guo, Lei Wang, Jian Zhang and Dongting Zhang

Fermentation 2024, 10(12), 656; https://doi.org/10.3390/fermentation10120656 - 18 Dec 2024

Viewed by 735

Abstract

When vegetable waste (VW) is used as a sole substrate for anaerobic digestion (AD), the rapid accumulation of volatile fatty acids (VFAs) can impede interspecies electron transfer (IET), resulting in a relatively low biogas production rate. In this study, Chinese cabbage and cabbage [...] Read more.

When vegetable waste (VW) is used as a sole substrate for anaerobic digestion (AD), the rapid accumulation of volatile fatty acids (VFAs) can impede interspecies electron transfer (IET), resulting in a relatively low biogas production rate. In this study, Chinese cabbage and cabbage were selected as the VW substrates, and four continuous stirred tank reactors (CSTRs) were employed. Different concentrations of biochar-loaded nano-Fe₃O₄(Fe₃O₄@BC) (100 mg/L, 200 mg/L, 300 mg/L) were added, and the organic loading rate (OLR) was gradually increased during the AD process. The changes in biogas production rate, VFAs, and microbial community structure in the fermentation tanks were analyzed to identify the optimal dosage of Fe₃O₄@BC and the maximum OLR. The results indicated that at the maximum OLR of 3.715 g (VS)/L·d, the addition of 200 mg/L of Fe₃O₄@BC most effectively promoted an increase in the biogas production rate and reduced the accumulation of VFAs compared to the other treatments. Under these conditions, the biogas production rate reached 0.658 L/g (VS). Furthermore, the addition of Fe₃O₄@BC enhanced both the diversity and abundance of bacteria and archaea. At the genus level, the abundance of Christensenellaceae_R-7_group, Sphaerochaeta, and the archaeal genus Thermovirga was notably increased. Full article

(This article belongs to the Special Issue Towards the Sustainable Treatment of Organic Wastes via Various Novel Biotechnologies)

► Show Figures

Graphical abstract

16 pages, 11300 KiB

Open AccessArticle

Improvement in Palm Kernel Meal Quality by Solid-Sate Fermentation with Bacillus velezensis, Saccharomyces cerevisiae and Lactobacillus paracasei

by Xiaoyan Zhu, Zechen Deng, Qiuyue Wang, Shanxin Hao, Pei Liu, Shuai He and Xiangqian Li

Fermentation 2024, 10(12), 655; https://doi.org/10.3390/fermentation10120655 - 17 Dec 2024

Viewed by 692

Abstract

To improve the quality of palm kernel meal (PKM), the effect of solid-state fermentation (SSF) with Bacillus velezensis, Saccharomyces cerevisiae and Lactobacillus paracasei on nutritional components, anti-nutritional factor and antioxidant activity were investigated. The results show that inoculation ratio of three strains [...] Read more.

To improve the quality of palm kernel meal (PKM), the effect of solid-state fermentation (SSF) with Bacillus velezensis, Saccharomyces cerevisiae and Lactobacillus paracasei on nutritional components, anti-nutritional factor and antioxidant activity were investigated. The results show that inoculation ratio of three strains 4:2:1, inoculation amount 21%, moisture content 52%, fermentation temperature 34 °C and fermentation time 60 h were the optimal SSF conditions. After 60 h of fermentation, the content of neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose and hemicellulose in PKM were significantly decreased by 22.5%, 18.2%, 20.2%, 17.6% and 32.4%, respectively. Meanwhile, the content of crude protein, soluble protein, peptides, amino acids and reducing sugar were increased significantly by 27.3%, 193%, 134%, 16.3% and 228%, respectively. SSF significantly improved the total phenolic content, DPPH radical scavenging activity, hydroxyl radical scavenging activity and reducing power. In addition, in vitro dry matter digestibility (IVDMD) and in vitro crude protein digestibility (IVCPD) were increased. Scanning electron microscopy (SEM) analysis revealed microstructural alterations in PKM. The results indicate that SSF with B. velezensis, S. cerevisiae and L. paracasei is an effective and promising method to enhance the nutritional value and antioxidant activity of PKM, providing a feasible solution for increasing the utilization of PKM in animal feed. Full article

(This article belongs to the Section Industrial Fermentation)

► Show Figures

Figure 1

14 pages, 1851 KiB

Open AccessArticle

Effects of Fresh Corn Stover to Corn Flour Ratio on Fermentation Quality and Bacterial Community of Mixed Silage

by Jintong Li, Ke Wu, Jiaxuan Wu, Chuang Yang, Baoli Sun, Ming Deng, Dewu Liu, Yaokun Li, Guangbin Liu and Yongqing Guo

Fermentation 2024, 10(12), 654; https://doi.org/10.3390/fermentation10120654 - 17 Dec 2024

Viewed by 1007

Abstract

Due to the high price of whole-plant corn silage in southern China, many dairy farms are attempting to prepare whole-plant corn silage using corn stover and corn flour, but the mixing ratio has not yet been determined. Therefore, we mixed fresh corn stover [...] Read more.

Due to the high price of whole-plant corn silage in southern China, many dairy farms are attempting to prepare whole-plant corn silage using corn stover and corn flour, but the mixing ratio has not yet been determined. Therefore, we mixed fresh corn stover and corn flour at the proportions of 100:0 (F0 group) to 80:20 (F20 group), using five groups with three replicates each. The optimal mixing ratio was determined by assessing the nutritional composition, fermentation quality, and bacterial community of silage after 45 days. The results showed that dry matter and water-soluble carbohydrates in silage increased linearly with the increasing ratio of corn flour (p < 0.01) while crude protein, true protein, neutral detergent fiber, acidic detergent fiber, and crude ash content decreased linearly (p < 0.01). The F0 group had the highest pH, and the mixing ratio quadratically affected ammonia nitrogen concentration (p < 0.05). Additionally, at the phylum level, the relative abundances of Proteobacteria and Cyanobacteria in the F15 group were significantly higher than in other groups (p < 0.05). At the genus level, Lactobacillus increased with corn flour inclusion compared to the F0 group. In conclusion, the silage quality is the best when the mixing ratio of fresh corn stover and corn flour is 85:15. Full article

(This article belongs to the Section Industrial Fermentation)

► Show Figures

Figure 1

Figure 1
Principal coordinate analysis (PCoA) of bacterial communities for fresh corn stover and corn flour mixed silage. Full article ">Figure 2
Accumulation map of bacterial communities at the phylum (A) and genus (B) levels for mixed silage. Full article ">Figure 2 Cont.
Accumulation map of bacterial communities at the phylum (A) and genus (B) levels for mixed silage. Full article ">Figure 3
LEfSe analysis of bacterial biomarkers with different mixing ratios. (A) LDA score assessments of the size of differentiation among five groups with a threshold of two. (B) Cladogram of LEfSe analysis of bacterial abundance. Full article ">Figure 3 Cont.
LEfSe analysis of bacterial biomarkers with different mixing ratios. (A) LDA score assessments of the size of differentiation among five groups with a threshold of two. (B) Cladogram of LEfSe analysis of bacterial abundance. Full article ">Figure 4
Correlation analysis between quality of silage and the top ten bacterial genera. (Positive correlation is shown in red, and negative correlation is shown in blue; “*” denotes p < 0.05, and “**” denotes p < 0.01; and the color depth is proportional to the correlation value). Abbreviations: pH (Pondus Hydrogenii), NH3-N (Ammonia nitrogen), LA (Lactic acid), AA (Acetic acid), DM (Dry matter), CP (Crude protein), TP (True protein), WSC (Water-soluble carbohydrate), NDF (Neutral detergent fiber), ADF (Acid detergent fiber), and Ash (Crude ash). Full article ">

12 pages, 6475 KiB

Open AccessArticle

Characterization of Urease from Providencia sp. LBBE and Its Application in Degrading Urea and Ethyl Carbamate in Rice Wine

by Han Wang, Dandan Li, Sibao Zhu, Shuxian Guo, Jiahong Ding, Chuanchao Wu and Qingtao Liu

Fermentation 2024, 10(12), 653; https://doi.org/10.3390/fermentation10120653 - 17 Dec 2024

Viewed by 668

Abstract

Enzymatic degradation of the carcinogen ethyl carbamate (EC) and its precursor urea is a promising method for controlling EC levels in alcoholic beverages. However, limited enzymes with EC-hydrolyzing activity and low ethanol or acid tolerance hinder their practical application. Here, a new urease [...] Read more.

Enzymatic degradation of the carcinogen ethyl carbamate (EC) and its precursor urea is a promising method for controlling EC levels in alcoholic beverages. However, limited enzymes with EC-hydrolyzing activity and low ethanol or acid tolerance hinder their practical application. Here, a new urease with urea- and EC-hydrolyzing activities from Providencia sp. LBBE was characterized. The enzyme displayed considerable ethanol tolerance, retaining 42.4% activity after 1 h of incubation with 30% (v/v) ethanol at 37 °C. It exhibited broad pH tolerance (pH 3.0–8.0), with optimal pH 7.0 for EC and 7.5 for urea. After treatment at pH 4.5 and 5.0, it retained 41.3% and 59.4% activity, respectively. The K_m and V_max for EC and urea at pH 4.5 were 515.6 mM, 33.9 µmol/(min⸱mg) and 32.0 mM, 263.6 µmol/(min⸱mg), respectively. Using 6000 U/L purified enzyme at 30 °C for 9 h, 49.8% and 81.6% of urea was removed from rice wine (pH 4.5 and 7.0), respectively. No appreciable reduction in EC was observed under identical conditions, which may be ascribed to the minimal EC affinity. This study contributes to the future realization of the effective control of EC content in alcoholic beverages. Full article

(This article belongs to the Special Issue Safety and Quality in Fermented Beverages)

► Show Figures

Figure 1

Figure 1
Characterization of urease gene clusters and sequence alignment of structural subunit C. (A) Structures of bifunctional urease gene clusters reported to date. (B) Sequence alignment of structural C subunits of ureases. Ka_UreC (PDB No. 1FWJ), Bp_UreC (GenBank accession No. AGN36402.1), Lr_UreC (GenBank No. EDX42993.1), Pr_UreC (GenBank No. AKR75466.1), and Ps_UreC (GenBank accession No. ASM56437.1) represent the C subunit of ureases from K. aerogenes, L. reuteri CICC6124, B. paralicheniformis ATCC 9945a, P. rettgeri JNB815, and Providencia sp. LBBE. Metal ligands are marked by stars; residues that are important for urea binding or catalysis are highlighted by squares. Full article ">Figure 2
Phylogenetic analysis of urease C subunit. The neighbor-joining phylogenetic tree was constructed using MEGA 11 software with 100 bootstrap replicates. Full article ">Figure 3
Effects of temperature and pH on Ps_Urease activity and stability. (A,B) Effect of temperature on enzyme activity and stability, respectively. (C,D) Effect of pH on enzyme activity and stability, respectively. Full article ">Figure 4
Effects of ethanol concentration on Ps_Urease activity, stability, and Michaelis–Menten curves of enzymes towards EC and urea under different pH conditions. (A,B) Effect of ethanol on enzyme activity and stability, respectively. (C) Michaelis–Menten curves of enzyme towards urea at pH 4.5 and pH 7.0. (D) Michaelis–Menten curves of the enzyme towards EC at pH 4.5 and pH 7.0. Full article ">Figure 5
Evaluation of urea and EC degradation by recombinant Ps_Urease in rice wine. A final concentration of 6000 U/L of purified Ps_Urease was introduced into the wine samples, and subsequently, the mixture was incubated at 30 °C for 18 h. Full article ">

16 pages, 5274 KiB

Open AccessArticle

Efficient Production of N-Acetyl-β-D-Glucosamine from Shrimp Shell Powder Using Chitinolytic Enzyme Cocktail with β-N-Acetylglucosaminidase from Domesticated Microbiome Metagenomes

by Xiuling Zhou, Yang Huang, Yuying Liu, Delong Pan and Yang Zhang

Fermentation 2024, 10(12), 652; https://doi.org/10.3390/fermentation10120652 - 16 Dec 2024

Viewed by 1007

Abstract

The conventional methods used to produce N-acetyl-β-D-glucosamine (GlcNAc) from seafood waste require pretreatment steps that use acids or bases to achieve the extraction and decrystallization of chitin prior to enzymatic conversion. The development of an enzymatic conversion method that does not require the [...] Read more.

The conventional methods used to produce N-acetyl-β-D-glucosamine (GlcNAc) from seafood waste require pretreatment steps that use acids or bases to achieve the extraction and decrystallization of chitin prior to enzymatic conversion. The development of an enzymatic conversion method that does not require the pretreatment of seafood waste is essential for the efficient and clean production of GlcNAc. In this study, the annotated metagenomic assembly data of domesticated microbiota (XHQ10) were analyzed to identify carbohydrate-active enzymes (CAZymes), and an in-depth analysis of the high-quality genome FS13.1, which was obtained from metagenomic binning, was performed; this enabled us to elucidate the catabolic mechanism of XHQ10 by using shrimp shell chitin as a carbon and nitrogen source. The only β-N-acetylglucosaminidase (named XmGlcNAcase) was cloned from FS13.1 and biochemically characterized. The direct production of GlcNAc from shrimp shell powder (SSP) via the use of a chitin enzyme cocktail was evaluated. Under the action of a chitin enzyme cocktail containing 5% recombinant XmGlcNAcase and a crude XHQ10 enzyme solution, the yield and purity of the final conversion of SSP to GlcNAc were 2.57 g/L and 82%, respectively. This is the first time that metagene-derived GlcNAcase has been utilized to achieve the enzymatic conversion of untreated seafood waste, laying the foundation for the low-cost and sustainable production of GlcNAc. Full article

(This article belongs to the Special Issue Towards the Sustainable Treatment of Organic Wastes via Various Novel Biotechnologies)

► Show Figures

Figure 1

Figure 1
Carbohydrate active enzymes (CAZymes) annotation analysis of the XHQ10 metagenome. (a) Column chart of the relative distribution of each sample on CAZy class; (b) degradation-related CAZy family clustering heat map of each sample in chitin; (c) column chart of KO LEfSe analysis of KEGG database, LDA ≥ 3.2. Full article ">Figure 2
Genome analysis of bin.FS13.1. (a) Classical circular genome maps of bin.FS13.1, from the inner circle to the outermost. Each circle represents the genome size (1), GC skew (2), GC content (3), contigs (4), CDS (5), chitinolytic enzymes (6). (b) Phylogenetic tree analysis and domain organization of chitinolytic enzymes. Full article ">Figure 3
Chitin and GlcNAc metabolic function annotation and the proposed pathway of chitin degradation in bin. FS13.1. Full article ">Figure 4
Bioinformatics analysis of XmGlcNAcase. (a) Phylogenetic tree analysis of XmGlcNAcase. (b) Multiple alignments of amino acid sequences of XmGlcNAcase, QKX94056.1, BAK53904.1, and AOY00075.1. (c) XmGlcNAcase conserved domain analysis. Full article ">Figure 5
Effect of temperature and pH on XmGlcNAcase. (a) The optimal temperature of XmGlcNAcase. (b) The stability of XmGlcNAcase at various temperature values. (c) The optimal pH of XmGlcNAcase. (d) The stability of XmGlcNAcase at various pH values. Full article ">Figure 6
The recombinant XmGlcNAcase coordinates with chitin-degrading enzymes. (a) The combined action of recombinant XmGlcNAcase and chitinase enhances chitin degradation. (b) Time course of GlcNAc production by different chitin enzyme cocktails. * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001. Full article ">

14 pages, 578 KiB

Open AccessArticle

The Effect of a Leaf Fertilization Method Using Humic Acids on the Minerality and Chemical Composition of Sauvignon Blanc Wine from the Slovak Wine Region

by Martin Bartkovský, Boris Semjon, Ivana Regecová, Viera Baričičová, Peter Očenáš, Lucia Šuľáková and Slavomír Marcinčák

Fermentation 2024, 10(12), 651; https://doi.org/10.3390/fermentation10120651 - 16 Dec 2024

Viewed by 864

Abstract

The objective of this study was to analyze the minerals transferred to Sauvignon blanc must and wine as an effect of foliar fertilizer application. The mineral composition was determined via atomic absorption spectroscopy. Experimental leaf and berry samples were examined during the phenological [...] Read more.

The objective of this study was to analyze the minerals transferred to Sauvignon blanc must and wine as an effect of foliar fertilizer application. The mineral composition was determined via atomic absorption spectroscopy. Experimental leaf and berry samples were examined during the phenological grapevine growth phases. A foliar fertilizer mixture (0.5 L/hL) with humic acids (8.51%) and B (0.031 kg) was applied. It was observed that the application of humic acids and boron significantly influenced the quality of Sauvignon blanc wine samples. During the blooming period, there was a statistically significant increase (p < 0.05) in P, K, and B in the experimental group. The results showed that using HAs and B in foliar fertilizer significantly (p < 0.05) increased the concentration of minerals in the experimental group. However, P and Fe content in the leaves decreased after veraison. After processing the berries in the vinification process, the levels of B in the must (0.71 ± 0.06 mg/kg) and, subsequently, in the wine (0.61 ± 0.06 mg/kg) were significantly (p < 0.05) higher in the experimental group. Data showed that the foliar fertilizer significantly increased the concentration of N (176.24 ± 0.02 mg/L) in the experimental must. These changes were also observed in wine samples. In wine, a statistically significant decrease in Ca (82.86 ± 0.29 mg/kg) was observed. Full article

(This article belongs to the Special Issue Fermentation and Biotechnology in Wine Making)

► Show Figures

Figure 1

11 pages, 729 KiB

Open AccessArticle

Evaluation of a Novel Potentially Probiotic/Pediococcus acidilactici ORE5 in Lactic Acid Fermentation of Cornelian Cherry Juice: Assessment of Nutritional Properties, Physicochemical Characteristics, and Sensory Attributes

by Ioanna Mantzourani, Maria Daoutidou, Antonia Terpou and Stavros Plessas

Fermentation 2024, 10(12), 650; https://doi.org/10.3390/fermentation10120650 - 16 Dec 2024

Viewed by 776

Abstract

The present research survey aimed to investigate the effect of a novel, potentially probiotic strain Pediococcus acidilactici ORE5 on the fermentation of Cornelian cherry for 24 h at 30 °C, followed by cold storage for 4 weeks. Two fermentation systems were established, differing [...] Read more.

The present research survey aimed to investigate the effect of a novel, potentially probiotic strain Pediococcus acidilactici ORE5 on the fermentation of Cornelian cherry for 24 h at 30 °C, followed by cold storage for 4 weeks. Two fermentation systems were established, differing in the form of P. acidilactici ORE5 applied as starter culture of (i) free cells and (ii) immobilized cells in delignified wheat bran. A high lactic acid fermentation rate was recorded, especially in the case of immobilized cell application, since lactic acid levels were determined at 184.8 mg/100 mL and acetic acid at 12.7 mg/100 mL. High probiotic load was observed throughout all studied periods, even at the fourth week of cold storage for both fermentation systems (above 8 log cfu/mL). The total phenolics content (TPC) of the fermented juices was high elevated compared to the unfermented one in all studied periods. When immobilized cells were applied, the TPC of the fermented juice attained the highest values (224.4.5–285.1 mg GAE/100 mL) compared to the juice fermented with free cells (204.5–258.4 mg GAE/100 mL) and the unfermented juice (140.5–165.8 mg GAE/100 mL). Improvements in the sensorial features of the fermented juice compared to the unfermented were also recorded during cold storage. Overall, the results of the present research demonstrated that P. acidilactici ORE5 can be successfully applied in lactic acid fermentation of Cornelian cherry juice, leading to a functional product with increased nutritional value, high probiotic load, and improved sensorial features. Full article

(This article belongs to the Special Issue Lactic Acid Bacteria Metabolism)

► Show Figures

Figure 1

23 pages, 876 KiB

Open AccessReview

Exploring the Potential and Challenges of Fermentation in Creating Foods: A Spotlight on Microalgae

by Monize Bürck, Ailton Cesar Lemes, Mariana Buranelo Egea and Anna Rafaela Cavalcante Braga

Fermentation 2024, 10(12), 649; https://doi.org/10.3390/fermentation10120649 - 16 Dec 2024

Viewed by 1368

Abstract

Fermentation is an ancient bioprocess that harnesses the power of microorganisms to convert raw ingredients into valuable and safe food products. There has been a growing interest in using fermentation to create safe, nutritious, and sustainable foods, particularly with the incorporation of microalgae. [...] Read more.

Fermentation is an ancient bioprocess that harnesses the power of microorganisms to convert raw ingredients into valuable and safe food products. There has been a growing interest in using fermentation to create safe, nutritious, and sustainable foods, particularly with the incorporation of microalgae. This review highlights fermentation’s potential benefits and challenges, focusing on microalgae and its metabolites. Bioactive peptides released during microalgae fermentation have garnered attention for their potential health benefits, particularly their antidiabetic actions. Studies suggest that these peptides can help regulate blood glucose levels and improve insulin sensitivity, presenting a promising avenue for developing foods that nourish and contribute to disease prevention. As awareness grows regarding health and sustainability, there is an increasing demand for safe and sustainable food options. Fermented products, particularly those utilizing microalgae, are often perceived positively by among consumers owing to their perceived benefits. Educating consumers on the advantages of fermented foods, including their nutritional value and sustainability, can further enhance market acceptance and commercialization. Thus, the present work aims to explore the literature to study the potential and challenges of fermentation as a tool to produce sustainable foods, focusing on microalgae as an ingredient. Full article

(This article belongs to the Topic Fermented Food: Health and Benefit)

► Show Figures

Figure 1

21 pages, 2335 KiB

Open AccessReview

Research and Prospects of Enzymatic Hydrolysis and Microbial Fermentation Technologies in Protein Raw Materials for Aquatic Feed

by Qiang Wang, Zhitao Qi, Weilai Fu, Mingzhu Pan, Xidong Ren, Xian Zhang and Zhiming Rao

Fermentation 2024, 10(12), 648; https://doi.org/10.3390/fermentation10120648 - 16 Dec 2024

Viewed by 1215

Abstract

Aquaculture relies heavily on formulated feed, with feed costs accounting for approximately 50% of the total production expenses. High-protein feed is expensive, and some raw materials are dependent on imports. Organic waste, primarily from food scraps and agricultural residues, can be considered feed [...] Read more.

Aquaculture relies heavily on formulated feed, with feed costs accounting for approximately 50% of the total production expenses. High-protein feed is expensive, and some raw materials are dependent on imports. Organic waste, primarily from food scraps and agricultural residues, can be considered feed ingredients to reduce costs. Through fermentation, the nutritional value of these feeds can be enhanced, promoting the growth of aquatic animals, such as fish, and reducing overall costs. Enzymatic hydrolysis and microbial fermentation are commonly used bioprocessing methods, particularly suitable for unconventional feed sources. These methods not only enhance the nutritional value of the feed but also reduce the content of anti-nutritional factors, improving feed digestibility. Enzymatic hydrolysis is often combined with microbial fermentation to produce more efficient novel biofeeds. This synergistic approach enhances microbial fermentation efficiency and the degradation of macromolecules, further improving the nutritional value of the feed, promoting intestinal digestion and absorption, and enhancing animal production performance. Compared to treatments with single strains or enzymes, the synergistic fermentation of feed with microorganisms and enzymes shows more significant effects. This review summarizes the fermentation mechanisms and classifications of enzymatic hydrolysis and microbial fermentation in producing novel biofeeds. It also outlines the advantages of this synergistic process and its progress in aquatic animal production, providing a scientific basis for its broader application in aquaculture. Full article

(This article belongs to the Special Issue Applied Microorganisms and Industrial/Food Enzymes, 2nd Edition)

► Show Figures

Figure 1

Figure 1
General schematic of enzymatic hydrolysis and microbial fermentation in aquatic animal feed. This diagram illustrates three main steps: the cultivation of fermentation strains (including the selection of strains and enzymes, fermentation production, filtration, and lyophilization), monitoring of the fermentation process (fermentation parameter control), and substrate selection (crop residues, fish bones, and vegetable and fruit waste). These steps ultimately produce efficient aquaculture feed. Full article ">Figure 2
The role of enzymatic hydrolysis and microbial fermentation in feed fermentation. Initially, enzymatic hydrolysis breaks down complex organic compounds, increasing the nutrient availability and digestibility of the feed. Subsequently, microorganisms utilize the hydrolyzed substrate for fermentation. Under aerobic conditions, microorganisms metabolize glucose and other carbon sources through aerobic respiration, producing carbon dioxide and water and generating substantial ATP. In contrast, under anaerobic conditions, microorganisms ferment glucose into lactic acid or ethanol, producing less ATP. Full article ">Figure 3
Classification and main effects of microbial enzymes in aquatic feed fermentation. Part (A) illustrates the roles of different enzymes in aquatic animal feed, including enhancing growth rates, boosting immunity, improving water quality and feed utilization, reducing environmental pollution, and decreasing energy consumption. Part (B) showcases the applications of various microbial fermentations in feed, focusing on improving the health of aquatic animals, enhancing stress resistance, modulating immunity, and aiding nutrient digestion. It also highlights the inhibitionof pathogenic bacteria, improved water quality, and enhanced reproductive capabilities. Full article ">Figure 4
Using microbial–enzyme synergistic fermentation to produce aquaculture feed involves several steps. First, plant or animal substrates are used as raw materials, and specific enzymes and microorganisms are added for fermentation and digestion to generate more easily absorbable nutrients. Next, the pretreated feed is mixed and conditioned to form a powdered feed suitable for pelleting. This powdered feed is then pressed into pellets using a pellet mill. Through further mixing and conditioning, the final product is a uniform, nutrient-rich, and easily digestible aquaculture feed. This feed is supplied to farmed fish and shrimp to promote their healthy growth. Full article ">Figure 5
Future prospects for enzymatic hydrolysis and microbial fermentation technology: ① Select and isolate microbial strains with fermentation potential and determine their fermentation performance. ② Enhance specific functions of strains through directed evolution and high-throughput screening. ③ Use databases to screen and modify key enzymes through protein engineering techniques, evaluate their performance in laboratory tests, and scale up production. ④ Establish a co-fermentation database for microbes and enzymes and use data-driven approaches combined with experimental fermentation parameters to construct dynamic models of critical indicators, such as macronutrient, anti-nutritional factor degradation, and probiotic population abundance during the pre-digestion process (including pH, temperature, humidity, and time). These models will also guide and optimize the microbial–enzyme fermentation process. Full article ">

13 pages, 1541 KiB

Open AccessArticle

Bread-Making Quality and Reduction of Acrylamide Content Using Weissella confusa Strain V20 from Desert Plant Stipagrostis pungens as Sourdough Additive

by Imene Fhoula, Islem Dammak, Insaf Nachi, Imen Smida, Mnasser Hassouna and Imene Hadda Ouzari

Fermentation 2024, 10(12), 647; https://doi.org/10.3390/fermentation10120647 - 16 Dec 2024

Viewed by 731

Abstract

The impact of wheat sourdough inoculated with a promising lactic acid bacterium Weissella confusa V20, isolated from a Tunisian desert plant, on the quality characteristics of sourdough and bread as well as on acrylamide formation was evaluated. W. confusa V20 sourdough (SWc) did [...] Read more.

The impact of wheat sourdough inoculated with a promising lactic acid bacterium Weissella confusa V20, isolated from a Tunisian desert plant, on the quality characteristics of sourdough and bread as well as on acrylamide formation was evaluated. W. confusa V20 sourdough (SWc) did not provide high final acidity and could effectively metabolize sucrose, resulting in significant (p < 0.05) increases in glucose (44.5%) and fructose (84.2%) levels. A substantial decrease (p < 0.05) in free asparagine was observed upon fermentation, reducing from 16 ± 0.9 mg/100 g dry weight (d.w.) in the control dough with baker’s yeast (DBB) to 9.9 ± 0.4 mg/100 g d.w. in the dough inoculated with W. confusa V20 sourdough (DWc) and to 14.2 ± 0.2 mg/100 g d.w. in the dough produced with spontaneous sourdough (DSS). To improve the texture and flavor of the bread, the sourdough process should be further optimized in a strain-specific approach. V20 sourdough was more effective in enhancing the quality of the dough and bread compared to sourdough fermented with yeast. W. confusa V20 proved to be highly effective in reducing acrylamide levels, achieving a significant 62% decrease compared to the control. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

► Show Figures

Figure 1

20 pages, 5995 KiB

Open AccessArticle

Pasteurization and the Potential Anti-Obesity Function of Fermented Beverages: A Significant Increase in Nitrogen-Containing Aromatic Heterocyclic Compound Content

by Xiurong Wu, Ting Wang, Xiangzhen Nie, Yanglin Wu, Jinghan Wang, Haoming Wang, Rui Dai, Ronghan Liu, Yingying Cui, Miaoting Su, Yang Qiu and Xiantao Yan

Fermentation 2024, 10(12), 646; https://doi.org/10.3390/fermentation10120646 - 16 Dec 2024

Viewed by 825

Abstract

Obesity is a chronic disease that profoundly impacts human health, and the role of plant-based formulas (PBFs) in combating obesity has garnered significant interest. Studies have revealed that fermentation significantly enhances the taste, aroma, quality, and health benefits of PBF water extract, with [...] Read more.

Obesity is a chronic disease that profoundly impacts human health, and the role of plant-based formulas (PBFs) in combating obesity has garnered significant interest. Studies have revealed that fermentation significantly enhances the taste, aroma, quality, and health benefits of PBF water extract, with pasteurization being the preferred sterilization technology. However, few studies have investigated the effects of pasteurization on the active components and potential functions of PBF water extract fermentation broth. To examine the impact of pasteurization on fermented water extract of Millettia speciosa Champ (FH08F) and its potential anti-obesity properties, the components of FH08F and thermal-pasteurized FH08F (FH08FS) were analyzed in this study. The analysis revealed a substantial rise in ester content following sterilization. This can be attributed to the acidic environment that promotes the esterification reaction during the heating phase. Network pharmacology was employed to thoroughly examine seven active components of upregulated compounds (URCs) with potential obesity targets, which constituted 92.97% of the total URC content, and four of them were nitrogen-containing aromatic heterocyclic compounds (NAHCs), which accounted for 90.33% of the total URC content. Upregulated NAHCs appear to actively contribute to efficacy against obesity. Molecular docking analyses have shown that theophylline, an NAHC, has the strongest binding affinity with the obesity-related target PTGS2 (Prostaglandin G/H synthase 2, 5FLG). These results imply that theophylline may directly activate PKA/PKG-mediated phosphorylated hormone-sensitive lipase (p-HSL), thereby promoting lipolysis through the cAMP signaling pathway and stimulating the catabolism of triglycerides (TGs) to combat obesity. In conclusion, pasteurization substantially alters the composition of FH08F, and NAHCs are likely to play a significant role in its potential anti-obesity function. These findings provide a scientific foundation for the potential therapeutic effect of FH08FS on obesity and associated metabolic diseases. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

► Show Figures

Figure 1

Figure 1
Analysis of compounds before and after pasteurization of FH08F: (a) Partial least squares discriminant analysis (PLS-DA) score plot of the FH08FS group versus the FH08F group. Component 1 (X-axis) represents the predicted score of the first principal component, showing the difference between the sample groups. Component 2 (Y-axis) represents the orthogonal principal component score, displaying the differences within the sample groups. Each scatter point represents a sample, and the green scatter points and red scatter points represent the FH08F and FH08FS groups, respectively. The region marked by the ellipse is the 95% confidence interval of the sample point. (b) Volcano plot. Red dots, blue dots, and gray dots represent significantly upregulated, significantly downregulated, and nonsignificantly different compounds, respectively. The dot size indicates the variable importance in projection (VIP) of each compound. (c) Results of differential compound category analysis of the FH08FS group vs. the FH08F group. The numbers on the bar chart represent the number of changed compound types. Red indicates significant upregulation, and blue indicates significant downregulation. (d) Terpenoids downregulated after pasteurization. (e) Proportion of each compound among the upregulated compounds (URCs). (f) The structure of nitrogen-containing aromatic heterocyclic compounds (NAHCs). Full article ">Figure 1 Cont.
Analysis of compounds before and after pasteurization of FH08F: (a) Partial least squares discriminant analysis (PLS-DA) score plot of the FH08FS group versus the FH08F group. Component 1 (X-axis) represents the predicted score of the first principal component, showing the difference between the sample groups. Component 2 (Y-axis) represents the orthogonal principal component score, displaying the differences within the sample groups. Each scatter point represents a sample, and the green scatter points and red scatter points represent the FH08F and FH08FS groups, respectively. The region marked by the ellipse is the 95% confidence interval of the sample point. (b) Volcano plot. Red dots, blue dots, and gray dots represent significantly upregulated, significantly downregulated, and nonsignificantly different compounds, respectively. The dot size indicates the variable importance in projection (VIP) of each compound. (c) Results of differential compound category analysis of the FH08FS group vs. the FH08F group. The numbers on the bar chart represent the number of changed compound types. Red indicates significant upregulation, and blue indicates significant downregulation. (d) Terpenoids downregulated after pasteurization. (e) Proportion of each compound among the upregulated compounds (URCs). (f) The structure of nitrogen-containing aromatic heterocyclic compounds (NAHCs). Full article ">Figure 2
Analysis of the targets associated with URCs and obesity: (a) Venn diagram of URCs and obesity-associated targets. This dataset included 193 URC-related targets (left), 1793 obesity-related targets (right), and 69 URCs and obesity-related targets. (b) URC anti-obesity PPI network. A larger area indicates larger nodes, a purple color indicates a stronger association and a lighter color indicates a weaker association. (c) The active ingredients of the URC–target–obesity interaction network. The active ingredients are sedanolide (Mol 3), ethyl-4-amino-2-(methylsulfanyl)-1,3-thiazole-5-carboxylate (Mol 10), nicotinamide (Mol 11), ethyl 2-{2-[(phenylsulfonyl)amino]-1,3-thiazol-4-yl}acetate (Mol 12), fumaric acid (Mol 14), theophylline (Mol 15), and 2-aminoethylphosphonate (Mol 17). (d) Degree values of the 7 active ingredients from <a href="#fermentation-10-00646-f002" class="html-fig">Figure 2</a>c. (e) Nineteen genes screened from the PPI network with BC, CC, DC, EC, LAC, and NC scores above the median value of 66 genes. (f) Seven core targets screened from the 19 targets with BC, CC, DC, EC, LAC, and NC scores above the median value. Full article ">Figure 2 Cont.
Analysis of the targets associated with URCs and obesity: (a) Venn diagram of URCs and obesity-associated targets. This dataset included 193 URC-related targets (left), 1793 obesity-related targets (right), and 69 URCs and obesity-related targets. (b) URC anti-obesity PPI network. A larger area indicates larger nodes, a purple color indicates a stronger association and a lighter color indicates a weaker association. (c) The active ingredients of the URC–target–obesity interaction network. The active ingredients are sedanolide (Mol 3), ethyl-4-amino-2-(methylsulfanyl)-1,3-thiazole-5-carboxylate (Mol 10), nicotinamide (Mol 11), ethyl 2-{2-[(phenylsulfonyl)amino]-1,3-thiazol-4-yl}acetate (Mol 12), fumaric acid (Mol 14), theophylline (Mol 15), and 2-aminoethylphosphonate (Mol 17). (d) Degree values of the 7 active ingredients from <a href="#fermentation-10-00646-f002" class="html-fig">Figure 2</a>c. (e) Nineteen genes screened from the PPI network with BC, CC, DC, EC, LAC, and NC scores above the median value of 66 genes. (f) Seven core targets screened from the 19 targets with BC, CC, DC, EC, LAC, and NC scores above the median value. Full article ">Figure 3
GO and KEGG pathway enrichment analysis of the targets associated with URCs against obesity: (a) GO enrichment analysis; (b) KEGG pathway enrichment analysis. Full article ">Figure 4
Heatmap of the molecular docking binding energy among 3 core active ingredients of URCs and 7 core targets. Full article ">Figure 5
Molecular docking diagram of theophylline and 7 core targets, the orange represents the theophylline molecule: (a) Theophylline-IL6; (b) theophylline-AKT1; (c) theophylline-PPARG; (d) theophylline-PTGS2; (e) theophylline-ESR1; (f) theophylline-PPARA; (g) theophylline-REN. Full article ">

40 pages, 2872 KiB

Open AccessReview

The Immunosuppressant Tacrolimus (FK506) Facing the 21st Century: Past Findings, Present Applications and Future Trends

by Carlos Barreiro, Ana Ibañez, Sonia Garrido-Chamorro and José Luis Barredo

Fermentation 2024, 10(12), 645; https://doi.org/10.3390/fermentation10120645 - 16 Dec 2024

Viewed by 1558

Abstract

The confluence of a large variety of factors, achievements and developments has resulted in the current long-term success in graft transplants. Some of these events are reviewed, paying special attention to immunosuppressant drugs, which are one of the most relevant milestones in the [...] Read more.

The confluence of a large variety of factors, achievements and developments has resulted in the current long-term success in graft transplants. Some of these events are reviewed, paying special attention to immunosuppressant drugs, which are one of the most relevant milestones in the prevention of organ transplant rejection. The discovery, industrial exploitation, mechanisms of action and side effects of several drugs exhibiting immunosuppressive effects (e.g., corticosteroids, nitrogen mustards, mycophenolic acid, rapamycin) are deeply detailed. Furthermore, new trends in immunosuppressant research, improvement and reformulation are also reviewed. Nevertheless, the core of the manuscript is the immunosuppressant tacrolimus, also called FK506, which has been sought after due to the commercial success of cyclosporine and other immunosuppressant compounds, but also because of the side effects of those previous compounds. Thus, in the mid-1980s tacrolimus was described as a more potent immunosuppressive molecule, with less undesirable effects. Currently, tacrolimus is a well-stablished API that is used as a clinical treatment to avoid graft rejection, but also shows interesting properties in terms of decreasing the impact of some autoimmune diseases and acting as an enhancer of nerve regeneration treatments. Thus, in the 40th anniversary of its discovery, this paper describes the current state of the art of this drug and how it is adapting to new social needs and clinical trends. Full article

(This article belongs to the Special Issue Feature Review Papers in Microbial Metabolism, Physiology & Genetics, 2nd Edition)

► Show Figures

Figure 1

Figure 1
Chemical structure of different immunosuppressant agents described throughout the text. Full article ">Figure 2
Scheme of the pathways controlled by the calcineurin inhibitors cyclosporine A (CsA) and tacrolimus (FK506). FKBP12 denotes the binding protein for tacrolimus, which inhibits calcineurin activity. CpN represents the cyclophilin molecule, which binds with cyclosporine A to similarly disrupt calcineurin. NFATc refers to nuclear factors of activated T cells, both phosphorylated (with a P) or dephosphorylated. The MAPKKK cascade pathway is also presented, highlighting its role in transmitting signals through a series of phosphorylation events that activate MAPKs, which subsequently regulate key cellular processes. Arrows with flat ends indicate inhibition, whereas arrows with pointed ends represent activation. The diagram provides a visual overview of how these immunosuppressive drugs exert their effects by disrupting both calcineurin activity and MAPK signalling pathways. Full article ">Figure 3
Gene cluster and biosynthetic pathway of tacrolimus (FK506). (A) Gene arrangement scheme of the biosynthetic cluster of tacrolimus. Gene colors define the different activities of the genes of the cluster. The central “PKS region” collects (i) the multifunctional FK506 polyketide synthase genes fkbA (cyan), fkbB (purple), and fkbC (light green); (ii) the gene responsible for the starter unit biosynthesis, fkbO (black); and (iii) the NPRS gene fkbP (dark green), which forms the macrolactone ring and release tacrolimus from the enzyme complex. Other subcluster genes are labelled as follows: (i) red, tcsABCD/allAKRD genes involved in allylmalonyl-CoA biosynthesis; (ii) yellow, fkbGHIJK genes involved in methoxymalonyl-ACP biosynthesis; (iii) orange, fkbL gene leading the pipecolate biosynthesis; (iv) pink, fkbDM genes involved in post-PKS modifications; (v) white, regulation-related genes (tcs2/allN, fkbN and tcs7/fkbR); (vi) dark brown, the thioesterase gene fkbQ; (vii) grey, genes with unknown function (tcs1345/allMPOS and tcs6). Light purple boxes represent a species-dependent feature, highlighting those genes just observed in the largest version of the tacrolimus biosynthesis cluster. (B) Tacrolimus biosynthetic pathway. Modules of the PKSs (bottom-right panel) include the following domains: CAS, CoA synthetase; ER, enoyl reductase; ACP, acyl carrier protein; KS, ketoacyl synthase; AT, acyl transferase; DH, dehydratase; KR, keto reductase. Bottom square presents the final structure of FK506 and two by-products of tacrolimus biosynthesis [ascomycin (KF520) or 37,38-dihydro-FK506 (FK506D)] (based on Huang and co-workers [<a href="#B214-fermentation-10-00645" class="html-bibr">214</a>], Barreiro and Martínez-Castro [<a href="#B181-fermentation-10-00645" class="html-bibr">181</a>], Ban and co-workers [<a href="#B215-fermentation-10-00645" class="html-bibr">215</a>]). Full article ">

12 pages, 3643 KiB

Open AccessArticle

The Enhancing Effect of Biochar Derived from Biogas Residues on the Anaerobic Digestion Process of Pig Manure Water

by Zhanjiang Pei, Xiao Wei, Shiguang Jin, Fengmei Shi, Jie Liu, Su Wang, Pengfei Li, Yifei Luo, Yongkang Wang, Tengfei Wang, Zenghui Ma, Yinxue Li and Yanling Yu

Fermentation 2024, 10(12), 644; https://doi.org/10.3390/fermentation10120644 - 15 Dec 2024

Viewed by 849

Abstract

Biochar-based additives can enhance the ability to produce methane during anaerobic digestion (AD), and biogas residues (BRs) are solid waste that can cause environmental pollution. Therefore, in this work, BRs were used as raw material to prepare biochar, and Fe³⁺ was used [...] Read more.

Biochar-based additives can enhance the ability to produce methane during anaerobic digestion (AD), and biogas residues (BRs) are solid waste that can cause environmental pollution. Therefore, in this work, BRs were used as raw material to prepare biochar, and Fe³⁺ was used to modify biochar for use in the AD process, generating pig manure water (PMW). The results showed that biogas residue biochar (BRB) showed good pore size and had a “honeycomb structure” on its surface. The commercially available iron–carbon composite material (Fe-C) showed the greatest cumulative methane production (CMP), the greatest removal rates of chemical oxygen demand (COD), and the greatest degradation rate of volatile fatty acids (VFAs), with the order of Fe-C > Fe³⁺-modified biogas residue biochar (FBRB) > BRB > control group. Fe³⁺ and Fe⁰ showed similar effects, where both could enhance the methanogenesis performance of anaerobic digestion by promoting direct interspecific electron transfer, and Fe⁰ was slightly more effective than Fe³⁺. Bacteroidotas and Firmicutes were the predominant phyla, and Clostridium_sensu_stricto_1 was the predominant genus. The addition of biochar and Fe³⁺ promoted the transformation of microorganisms from the conventional metabolic mode into an efficient metabolic mode. Extracellular electron transfer played a crucial role in this. Full article

(This article belongs to the Special Issue Anaerobic Digestion of Sewage Sludge: New Insights and Future Challenges)

► Show Figures

Figure 1

23 pages, 1457 KiB

Open AccessArticle

Beneficial Effects of Maternal Supplementation of Yeast Single-Cell Protein on Suckling Piglets by Altering Sow Gut Microbiome and Milk Metabolome

by Zhongping Chen, Biao Li, Yong Zhuo, Yonggang Zhang and Guoshun Chen

Fermentation 2024, 10(12), 643; https://doi.org/10.3390/fermentation10120643 - 15 Dec 2024

Viewed by 587

Abstract

This study aimed to assess the impact of yeast single-cell protein (YP) supplementation in diets from late gestation through lactation on sow reproductive performance and the associated gut microbiome and metabolomic changes in milk. A total of 172 sows, at 103 days of [...] Read more.

This study aimed to assess the impact of yeast single-cell protein (YP) supplementation in diets from late gestation through lactation on sow reproductive performance and the associated gut microbiome and metabolomic changes in milk. A total of 172 sows, at 103 days of gestation, were randomly assigned to four treatment groups: a control group receiving 2% fishmeal and three groups receiving 0.5%, 1.0%, and 2.0% YP, replacing 0.3%, 0.6%, and 1.5% fishmeal, respectively. No significant effects were observed on litter performance in sows. The inclusion of 2% YP displayed an augmented litter weight gain and piglet weight gain during lactation. Microbial sequencing revealed a marked decrease in Enterobacteriaceae abundance in sow feces at day 113 of gestation following dietary YP supplementation. Moreover, it led to a notable reduction of microbial-associated lipids, such as endotoxin, in serum and milk. In summary, YP supplementation in sow diets reduced gut pathogenic microbiota and their components, contributing to enhanced growth performance in suckling piglets. Full article

(This article belongs to the Special Issue New Ways of Production of Single Cell Proteins for Future Food or Feed by Fermentation)

► Show Figures

Figure 1

12 pages, 1083 KiB

Open AccessArticle

Influence of Plant Protein Fining Agents on the Phenolic Composition of Organic Grape Musts

by Áron Pál Szövényi, Annamária Sólyom-Leskó, Anna Szabó, Balázs Nagy, Zsuzsanna Varga and Diána Ágnes Nyitrainé Sárdy

Fermentation 2024, 10(12), 642; https://doi.org/10.3390/fermentation10120642 - 14 Dec 2024

Viewed by 510

Abstract

Protein-based clarification agents were tested to clarify Chardonnay grape musts during sedimentation. The experiments were conducted in the Etyek–Buda Wine Region in Northwest Hungary over four vintages between 2020 and 2023. The performance of the treatment agents was influenced by several factors, such [...] Read more.

Protein-based clarification agents were tested to clarify Chardonnay grape musts during sedimentation. The experiments were conducted in the Etyek–Buda Wine Region in Northwest Hungary over four vintages between 2020 and 2023. The performance of the treatment agents was influenced by several factors, such as the composition of the grape must (the absolute concentration and the relative ratio of phenolic compounds) which varied with the vintage characteristics, the physiological and phenolic ripeness of the grapes, and the composition of the clarifying agents itself. Recent investigations show that fully ripe fruit juices can be clarified more effectively, and the effectiveness increases when different types of clarification agents are combined with the plant proteins, e.g., PVPP greatly facilitates the removal of phenolic compounds. The tested plant protein-based clarification agents did not influence the YAN source of the grape musts before fermentation. Our investigations proved an effective impact of these preparations even during the first steps of wine technology. Sensory properties and chemical stability are improved by decreasing the polyphenol content before fermentation, and, besides the good technological effects, wines treated with plant protein agents can be included in the vegan diet. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

► Show Figures

Figure 1

Figure 1
Total polyphenolic content of clarified grape juices and wines in four vintages, clarified with different plant protein agents before fermentation. (Deep-coloured sections with white digits show TP in the clarified grape juices; light-coloured sections with black digits indicate the removed phenolic content (calculated data); full-height columns show the initial TP of grape juices; dark notch markers indicate TP in the wines after fermentation. Data are expressed in mg gallic acid per litre). Full article ">Figure 2
Catechin content of clarified grape juices and wines in four vintages, clarified with different plant protein agents before fermentation. (Deep-coloured sections with white digits show the catechin content of the clarified grape juices; light-coloured sections with black digits indicate the removed catechins (calculated data); full-height columns show the initial catechin content of the grape juices; dark notch markers indicate the catechin content of the wines after fermentation. Data are expressed in mg catechin per litre). Full article ">Figure 3
Leucoanthocyanin content of clarified grape juices and wines in four vintages, clarified with different plant protein agents before fermentation. (Deep-coloured sections with white digits show the leucoanthocyanin content of the clarified grape juices; light-coloured sections with black digits indicate the removed leucoanthocyanins (calculated data); full-height columns show the initial leucoanthocyanin content of the grape juices; dark notch markers indicate the leucoanthocyanin content of the wines after fermentation. Data are expressed in mg malvidine-3,5-diglucoside per litre). Full article ">

18 pages, 2419 KiB

Open AccessArticle

Optimizing Ge Enrichment in Lyophyllum decastes Fermentation for Enhanced Biological Activity

by Syed Shaheer Hassan, Jinyan Zhao, Sana Tahir, Ilyas Khan, Guang Yang and Bo Zhao

Fermentation 2024, 10(12), 641; https://doi.org/10.3390/fermentation10120641 - 14 Dec 2024

Viewed by 510

Abstract

This study enhanced germanium (Ge) enrichment in the liquid fermentation of the edible fungus Lyophyllum decastes in order to boost its biological activity, particularly its antioxidant and immunomodulatory properties. Through the use of single-factor and Plackett–Burman designs, the experiments revealed critical parameters affecting [...] Read more.

This study enhanced germanium (Ge) enrichment in the liquid fermentation of the edible fungus Lyophyllum decastes in order to boost its biological activity, particularly its antioxidant and immunomodulatory properties. Through the use of single-factor and Plackett–Burman designs, the experiments revealed critical parameters affecting Ge enrichment, including Ge oxide concentration, potato powder concentration, and peptone levels. The optimization of the Box–Behnken response surface methodology resulted in a Ge concentration of 3.61 mg/L, significantly enhancing the biomass, protein, polysaccharide, and flavonoid content in the mycelium. In contrast to traditional fermentation, Ge-rich fermentation enhanced the mycelial biomass by 30.97% and elevated the organic Ge content 50.19-fold. An analysis of the antioxidants revealed that the Ge-enriched mycelial water extract exhibited heightened activity, augmenting TNF-α production in RAW264.7 cells by 73.29% at a concentration of 200 μg/g. These findings indicate that the Ge-enriched fermentation of L. decastes holds promise for functional applications in health-supportive products due to its robust antioxidant and immune-enhancing capabilities. Full article

(This article belongs to the Section Fermentation Process Design)

► Show Figures

Figure 1

Figure 1
Effects of Ge enrichment on biomass, organic Ge content, soluble protein content, and polysaccharide content. Uppercase and lowercase letters indicate significance at the p < 0.01 and p < 0.05 levels, respectively. The control group is 0 mg/L (a–d). Full article ">Figure 2
Correlation heatmap. Full article ">Figure 3
Three-dimensional response surface analysis. X1, X2, and X3 represent the Ge addition amount (mg/kg), potato powder concentration (g/L), and peptone concentration (g/L), respectively, while Y1 represents Ge enrichment. Full article ">Figure 4
Effect of the Ge enrichment on antioxidant and reducing activities of L. Decastes extracts (a–d). Full article ">Figure 5
Effects of the different culture methods on the NO content of RAW264.7 cells when L. decastes aqueous extracts were applied. Uppercase and lowercase letters indicate significance at the p < 0.01 and p < 0.05 levels, respectively. Full article ">Figure 6
Effects of the different culture methods used to obtain water extracts from L. decastes on the TNF-α content in the supernatant of RAW264.7 cells. Uppercase and lowercase letters indicate significance at the p < 0.01 and p < 0.05 levels, respectively. Full article ">

27 pages, 1597 KiB

Open AccessReview

Microbial Conversion of Inulin to Valuable Products: The Biorefinery Concept

by Lidia Tsigoriyna, Stefan Stefanov, Nadya Armenova, Penka Petrova and Kaloyan Petrov

Fermentation 2024, 10(12), 640; https://doi.org/10.3390/fermentation10120640 - 13 Dec 2024

Viewed by 1230

Abstract

The global transition to a sustainable bioeconomy requires the engagement of renewable and cost-effective substrates to obtain valuable bio-based products. Inulin-rich plant materials have promising applications in white biotechnology. This review evaluates the potential of converting inulin through an integrated biorefinery into high-value [...] Read more.

The global transition to a sustainable bioeconomy requires the engagement of renewable and cost-effective substrates to obtain valuable bio-based products. Inulin-rich plant materials have promising applications in white biotechnology. This review evaluates the potential of converting inulin through an integrated biorefinery into high-value products by microbial fermentation. It describes the methods for raw biomass and inulin pretreatment, the possibilities of simultaneous saccharification and fermentation (SSF), and the use of wild-type and genetically modified microbial strains. The bioconversion of inulin enables the efficient synthesis of biofuels such as ethanol, butanol, and 2,3-butanediol and biochemicals such as lactic, citric, and poly-γ-glutamic acid. By analyzing the advances in inulin hydrolysis methods, microbial engineering, and bioprocess optimization approaches, this review highlights the broad applicability of inulin in the biorefinery context as a multifunctional, sustainable substrate, which contributes to the development of the circular economy. Full article

(This article belongs to the Special Issue New Research on Strains Improvement and Microbial Biosynthesis, 2nd Edition)

► Show Figures

Figure 1

21 pages, 886 KiB

Open AccessArticle

Machine Learning Prediction of Foaming in Anaerobic Co-Digestion from Six Key Process Parameters

by Sarah E. Daly and Ji-Qin Ni

Fermentation 2024, 10(12), 639; https://doi.org/10.3390/fermentation10120639 - 13 Dec 2024

Viewed by 681

Abstract

Foaming in co-digested anaerobic digesters can reduce biogas production, leading to economic loss. However, the underlying causes of foaming are not completely understood. This study investigated a field-scale mesophilic digester system that experienced intermittent foaming, employing experimental and modeling methods over a 16-month [...] Read more.

Foaming in co-digested anaerobic digesters can reduce biogas production, leading to economic loss. However, the underlying causes of foaming are not completely understood. This study investigated a field-scale mesophilic digester system that experienced intermittent foaming, employing experimental and modeling methods over a 16-month period. Samples were collected during both foaming and non-foaming events and were thoroughly characterized for methane (CH₄) yields and different physical and chemical concentrations, including volatile solids (VS), metals, total phosphorus (TP), total chemical oxygen demand (TCOD), total volatile fatty acids (TVFAs), and total alkalinity (TALK). Machine learning techniques were applied to predict foaming events with several algorithms tested to optimize prediction accuracy. The results showed that digester liquid and effluent samples collected from foaming events had significantly lower (p < 0.05) average CH₄ yields (77 and 45 mL CH₄ g VS⁻¹) than during non-foaming events (150 and 83 mL CH₄ g VS⁻¹). Recursive feature modeling identified six key parameters (1. Fe(II):S; 2. Fe(II):TP; 3. TCOD; 4. Fe; 5. TVFA:TALK; and 6. Cu) associated with digester foaming. Among the tested machine learning models, the support vector machine (SVM) algorithm achieved the highest recognition accuracy of 87%. This study demonstrates that the interactions of multiple chemical and physical process parameters are an important consideration for predicting anaerobic digester foaming. Full article

(This article belongs to the Section Fermentation Process Design)

► Show Figures

Figure 1

27 pages, 3299 KiB

Open AccessReview

Advances in Biotechnological Strategies for Sustainable Production of Non-Animal Proteins: Challenges, Innovations, and Applications

by Emanuel do Nascimento Muniz, Rebeca Teixeira de Queiroz Montenegro, Daniel Nascimento da Silva, Alan Portal D’Almeida, Luciana Rocha Barros Gonçalves and Tiago Lima de Albuquerque

Fermentation 2024, 10(12), 638; https://doi.org/10.3390/fermentation10120638 - 13 Dec 2024

Cited by 1 | Viewed by 1238

Abstract

This review explores recent advances in the design of fermentation processes for producing alternative proteins, focusing on utilizing agro-industrial waste and renewable substrates. New bioprocess strategies, such as experimental designs, optimizing bioreactors, bioprocesses, and applying precision fermentation can improve the protein yields and [...] Read more.

This review explores recent advances in the design of fermentation processes for producing alternative proteins, focusing on utilizing agro-industrial waste and renewable substrates. New bioprocess strategies, such as experimental designs, optimizing bioreactors, bioprocesses, and applying precision fermentation can improve the protein yields and nutritional value. Also, unconventional substrates, such as hydrolysates derived from agro-industrial residues conversion may result in cost reduction and enhanced feasibility. The application of enzymes to produce protein-rich foods with high bioaccessibility that improve digestibility and nutritional value are also highlighted. This article addresses the importance of developing cost-effective fermentation solutions that minimize the environmental impact while addressing technical challenges such as scalability and contamination control. Furthermore, it emphasizes the growing need for innovations in fermentation process design to ensure the sustainability of industrial protein production. The review concludes that improvements in process design are fundamental in overcoming technological and regulatory barriers, particularly in increasing the efficiency and competitiveness of non-meat proteins in the global market. Full article

(This article belongs to the Special Issue Research on Microbial Protein Synthesis: 2nd Edition)

► Show Figures

Figure 1

14 pages, 1107 KiB

Open AccessArticle

Effect of Nitrite and Temperature on Autotrophic Denitrification in Anammox Granular Biomass from a Partial Nitritation–Anammox Reactor

by Benjamín Ibarra, Yves Lesty, Mateo Pastur, Celia Castro, Chloe Girard and Rolando Chamy

Fermentation 2024, 10(12), 637; https://doi.org/10.3390/fermentation10120637 - 12 Dec 2024

Viewed by 676

Abstract

Anaerobic ammonium oxidation (anammox) is a key process in the removal of nitrogen from wastewater, in which episodes of substrate inhibition may occur. In this study, the effect of nitrite on anammox in the short and long term was investigated using granules from [...] Read more.

Anaerobic ammonium oxidation (anammox) is a key process in the removal of nitrogen from wastewater, in which episodes of substrate inhibition may occur. In this study, the effect of nitrite on anammox in the short and long term was investigated using granules from a full-scale SBR reactor in operation. In the short term, maximum activity was achieved at 100 mg N-NO₂⁻/L, with higher concentrations being inhibitory. It was determined that the biomass behavior is well interpreted (R² = 0.955) by a non-competitive substrate inhibition model (Andrews model), with a K_S of 55.6 mg N-NO₂⁻/L and a K_I of 116.7 mg N-NO₂⁻/L, and also well interpreted by the Edwards model (R² = 0.957), with a K_S of 36 mg N-NO₂⁻/L and a K_I of 287 mg N-NO₂⁻/L. In the long term, the biomass retained its anammox activity at 15 mg N-NO₂⁻/L over a three TRH horizon; however, at 30 mg N-NO₂⁻/L, anammox activity decreased by 50% at the end of the experiment. Finally, the effect of temperature on the activity of the anammox granules from a different source was studied, revealing that the activity increases with temperature within the range of 25–35 °C, which can be useful if a rapid increase in activity is desired. Operationally, maintaining nitrite below 30 mg N-NO₂⁻/L ensures stability, while exceeding 100 mg N-NO₂⁻/L causes immediate SAA inhibition and slower recovery. Full article

(This article belongs to the Special Issue Treatment of Municipal Wastewater by Anaerobic Biotechnology)

► Show Figures

Figure 1

3 pages, 181 KiB

Open AccessEditorial

Advances in Research on Beverages, Food, Yeast and Brewing

by Ogueri Nwaiwu

Fermentation 2024, 10(12), 636; https://doi.org/10.3390/fermentation10120636 - 12 Dec 2024

Viewed by 593

Abstract

This closing Editorial marks the end of three volumes of this Special Issue (SI), which covered themes like changes in reactants and products, chemistry, sensory properties, microbiology, transcriptomics, proteomics and metabolomics, food safety, and nutrition [...] Full article

(This article belongs to the Special Issue Advances in Beverages, Food, Yeast and Brewing Research, 3rd Edition)

11 pages, 1208 KiB

Open AccessArticle

Development of High-Glucosinolate-Retaining Lactic-Acid-Bacteria-Co-Fermented Cabbage Products

by Chen-Che Hsieh, Yuan-Heng Liu, Shin-Ping Lin, Shella Permatasari Santoso, Kaemwich Jantama, Tsung-Yu Tsai, Chang-Wei Hsieh and Kuan-Chen Cheng

Fermentation 2024, 10(12), 635; https://doi.org/10.3390/fermentation10120635 - 12 Dec 2024

Viewed by 651

Abstract

Cabbage (Brassica oleracea var. capitata) is rich in dietary fiber, vitamins, trace elements, and functional components like glucosinolates, which are essential for promoting health. This study aims to enhance the health benefits and nutritional content of cabbage through lactic acid fermentation [...] Read more.

Cabbage (Brassica oleracea var. capitata) is rich in dietary fiber, vitamins, trace elements, and functional components like glucosinolates, which are essential for promoting health. This study aims to enhance the health benefits and nutritional content of cabbage through lactic acid fermentation using a bioreactor, with a particular focus on glucosinolate retention. The fermentation utilized a consortium of Lactiplantibacillus plantarum, known for its robust acidifying capabilities, and antioxidant-rich strains Lactobacillus acidophilus and Bifidobacterium longum. A 5 L bioreactor facilitated the controlled fermentation process (35 °C, 24 h of fermentation at 5 rpm). The efficacy of glucosinolate retention was quantitatively assessed alongside the analysis of antioxidant properties via 1,1-diphenyl-2-picrylhydrazil (DPPH) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The results indicated a notable enhancement in antioxidant capacity with a 16.32% increase in the DPPH radical scavenging rate compared to non-fermented cabbage. Glucosinolate retention was impressively sustained at 82.02% in bioreactor conditions. Storage stability tests conducted at 4 °C revealed minimal degradation of glucosinolates, maintaining significant levels up to 14 days (from 90.34% to 66.49%). This study underscores the potential of bioreactor-facilitated lactic acid fermentation in preserving and enhancing the nutritional and functional qualities of cabbage, thereby extending its market value and promoting sustainable agricultural practices. Full article

(This article belongs to the Special Issue Application of Lactic Acid Bacteria in Fermented Food: 2nd Edition)

► Show Figures

Figure 1

Figure 1
The antioxidant activity of fresh cabbage and LAB fermented cabbage. Each value is expressed as means (n = 3), and standard deviations are shown as error bars. Values marked by ** (p < 0.01) are significantly different according to an independent sample t-test. Fresh: fresh cabbage, fermented: fermented cabbage. Full article ">Figure 2
Phenolic contents of fresh cabbage and lactic-acid-fermented cabbage. Each value is expressed as means (n = 3), and standard deviations are shown as error bars. Values marked by * (p < 0.05) and ** (p < 0.01) are significantly different according to an independent sample t-test. Fresh: fresh cabbage, fermented: fermented cabbage. Full article ">Figure 3
The total flavonoid contents of fresh cabbage and lactic-acid-fermented cabbage. Each value is expressed as means (n = 3), and standard deviations are shown as error bars. Fresh: fresh cabbage, fermented: fermented cabbage. Full article ">Figure 4
The total glucosinolate retention of lactic-acid-fermented cabbage produced by different processes. Each value is expressed as means (n = 3), and standard deviations are shown as error bars. Values marked by different letters are significantly different according to Duncan’s multiple range test (p < 0.05). Salted: dehydrated cabbage by salted; canned: lactic-acid-fermented cabbage produced via small-scale production; bioreactor-0.3%: lactic-acid-fermented cabbage produced via the 5 L bioreactor with a 0.3% microbial inoculation size; bioreactor-3.0%: lactic-acid-fermented cabbage produced via the 5 L bioreactor with a 3.0% microbial inoculation size. Full article ">

16 pages, 2528 KiB

Open AccessArticle

Continuous Production of Chitin Oligosaccharides Utilizing an Optimized Enzyme Production-Adsorption-Enzymolysis-Product Separation (EAES) System

by Xiuling Zhou, Yang Huang, Yuying Liu, Delong Pan and Yang Zhang

Fermentation 2024, 10(12), 634; https://doi.org/10.3390/fermentation10120634 - 12 Dec 2024

Viewed by 598

Abstract

Chitin oligosaccharide (CHOS) is a chitin derivative with excellent biological activities. Enzymatic hydrolysis of chitin-rich biomass into CHOS is a hot topic in research on the high-value utilization of chitin resources. The disadvantages of complex preparation and purification processes and the high cost [...] Read more.

Chitin oligosaccharide (CHOS) is a chitin derivative with excellent biological activities. Enzymatic hydrolysis of chitin-rich biomass into CHOS is a hot topic in research on the high-value utilization of chitin resources. The disadvantages of complex preparation and purification processes and the high cost of chitin-degrading enzymes limit large-scale enzymatic production and application of CHOS. In this study, the activity of chitinase increased from 1.8 U/mL to 3.52 U/mL by 94.4% after optimizing the carbon and nitrogen source of Chitiniphilus sp. LZ32 fermentation. An enzyme production-adsorption-enzymolysis-product separation (EAES) system was constructed using fermentation, an adsorption purification module, and a product ultrafiltration module of a chitin-degrading enzyme. CHOS production by continuous enzymatic hydrolysis was performed in an EAES system using housefly larval powder (HLP) as the substrate. After the C. sp. LZ32 fermentation broth was circulated in the adsorption module for 90 min, the adsorption rate of the chitin-degrading enzyme reached more than 90%. The ultrafiltration module effectively separated CHOS at an operating pressure of 2 bar. Four batches of CHOS were produced in the EAES system using repeated batch fermentation. The running time of a single batch decreased from 115 h in the first batch to 48 h, and the CHOS output of each batch gradually increased. The total CHOS output was 61 g, and the production efficiency was 0.24 g/h. The CHOS produced by the EAES system (ECHOS) has high antioxidant activity. In this study, the EAES system was used to simplify the purification and separation steps of CHOS preparation, and the continuous production of CHOS was realized, which has potential application prospects in the field of green CHOS production. Full article

(This article belongs to the Special Issue Metabolic Engineering in Microbial Synthesis)

► Show Figures

Figure 1

Figure 1
Schematic of EAES system. Full article ">Figure 2
Optimization of carbon and nitrogen sources in the medium. (a) Effects of carbon sources on biomass and chitin enzyme activities. (b) Effect of sucrose concentration on biomass and chitin enzyme activity. (c) Effects of nitrogen sources on biomass and chitin enzyme activities. (d) Effect of nitrogen concentration on biomass and chitin enzyme activities. Full article ">Figure 3
The biomass and enzyme activity of C. sp. LZ32 during fermentation in (a) batch and (b) repeated batches. Full article ">Figure 4
Effects of different flow rates on adsorption and bacterial interception of chitin-degrading enzymes. Full article ">Figure 5
Changes in the proportions of (a) membrane flux and (b) CHOS with different degrees of polymerization during CHOS ultrafiltration separation. Full article ">Figure 6
Changes in CHOS accumulation and permeate flux in the EAES system in the repeated batch operation mode. Full article ">Figure 7
EAES system produces CHOS antioxidant activity. (a) Scavenging effect of ECHOS on hydroxyl radical-scavenging; (b) scavenging effect of ECHOS on DPPH radical scavenging; (c) reducing power of ECHOS. Full article ">

Journal Menu

Journal Browser

Fermentation, Volume 10, Issue 12 (December 2024) – 70 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI