EP4408563A1

EP4408563A1 - Polyalkylene alkyl compound for defoaming fermentation broth

Info

Publication number: EP4408563A1
Application number: EP21798547.2A
Authority: EP
Inventors: Wenjing QI; Zeyu ZHONG; Xue CHEN
Original assignee: Dow Global Technologies LLC
Current assignee: Dow Global Technologies LLC
Priority date: 2021-09-29
Filing date: 2021-09-29
Publication date: 2024-08-07
Also published as: WO2023050125A1; JP2024535199A; CN117897212A; KR20240070614A; CA3233001A1; AU2021466848A1

Abstract

The present invention relates to a method for inhibiting the formation of foam in a process comprising the step of adding an effective amount of a foam control agent to a process mixture. The foam control agent comprises a compound that can be represented by the formula, RO (EO) n (PO) mH, where R is a linear hydrocarbon radical having from 12 to 18 carbon atoms; EO is ethylene oxide; PO is propylene oxide; n can be any integer from 2 to 9; and m can be any integer from 8 to 19. Furthermore, the compounds can be characterized in that the molecular weight of R is from 8 to 29 percent by weight of the compound. These compositions have been found to be superior in controlling foam formation versus conventional antifoamers in fermentation, preferably in amino acids fermentation and enzyme fermentation, more preferably in lysine, MSG and glucose oxidase fermentation.

Description

HIGH PERFORMANCE FOAM CONTROL AGENTS IN FOOD ＆FEED FERMENTATION

FIELD

This invention relates to a method of inhibiting the formation of foam in industrial processes such as in fermentation broths.
INTRODUCTION
Foam is generated in almost any industrial process where a liquid, gas, foam-stabilizing surfactants and agitation are present. In most cases, foam is undesirable, especially in fermentation industry. Foaming is a nuisance during fermentation process because it causes process control issues and reduces the mechanical efficiency. For example, the existence of foam in fermentation tank may result in a prolonged fermentation cycle, reduce production capacity, waste raw materials, affect bacterial respiration, cause bacterial infection and may affect the quality of the finished products.
Current methods to control foam include mechanical means such as the use of baffles and mixing control systems. In conjunction, chemical defoamers or antifoamers are often used. There are different classes of additives used in prevention, removal and mitigation of foam formation that work via differing mechanisms and are effective for different foam types (e.g. macro vs micro foams) . While in principle these classes differ, the terms used to define them are often used interchangeably. In addition, many, if not most additives, do not solely perform only one function.
Antifoamers are additives that prevent or inhibit foam formation from the outset, and are typically added to a potentially foaming solution prior to foam formation. Defoamers are compounds that are added to mixtures in order to destroy foam that has already been generated, targeting surface foam (macro foam) and aiming to bring about rapid foam collapse. Deaerators function in a manner similar to defoamers, also aiming to destroy foam that has already been generated, but they target sub-surface foam (micro foam) . Well known defoamers, antifoamers and deaerators include amongst others, silicone oils as well as block copolymers of lower alkylene glycols.
There is however an ongoing need for improved stable, simple, low cost, aqueous defoamers, antifoamers and /or deaerators in concentrated form for effective application in the chemical, household and industrial process industries.
SUMMARY
The present invention relates to a method for inhibiting the formation of foam in a process comprising the step of adding an effective amount of a foam control agent to a process mixture. The foam control agent comprises a compound that can be represented by the formula, RO (EO) _n (PO) _mH, where R is a linear hydrocarbon radical having from 12 to 18 carbon atoms; EO is ethylene oxide; PO is propylene oxide; n can be any integer from 2 to 9; and m can be any integer from 8 to 19. Furthermore, the compounds can be characterized in that the molecular weight of R is from 10 to 29 percent by weight of the compound. These compositions have been found to be superior in controlling foam formation versus conventional antifoamers in fermentation, preferably in amino acids fermentation and enzyme fermentation, more preferably in lysine, MSG and glucose oxidase fermentation.

DETAILED DESCRIPTION

The present invention has utility in any process where a liquid and a gas are present and agitation or other means of surface interaction between the liquid and gas is present, as under such conditions foam has a tendency to be generated. In particular, the present invention has been found to have utility in controlling foaming in a fermentation broth. For purposes of this invention, "fermentation broth" means an aqueous dispersion of nutrients usually with microorganisms, from which a metabolic product is ultimately extracted. The microorganisms are preferably bacteria or fungi or yeast. Typical nutrients seen in fermentation comprise a source of carbon, nitrogen, salts, and organism-specific requirements. Typical carbon sources include monosaccharides, disaccharides, polysaccharides, alcohols, carboxylic acids, fats, and hydrocarbons. Nitrogen sources often also include carbon, and are exemplified by ammonia, urea, bean meal, grain meal, seed meal, fish meal, cornsteep liquor, and yeast extracts. Salts can be specifically added to the fermentation broth as well.
The method of the present invention comprises the step of adding an effective amount of a foam control agent to a process mixture. The foam control agent comprises a compound that can be represented by the formula, RO (EO) _n (PO) _mH, where R is a linear hydrocarbon radical having from 12 to 18 carbon atoms; EO is ethylene oxide; PO is propylene oxide; n can be any integer from 2 to 9 inclusive; and m can be any integer from 8 to 19 inclusive. Furthermore, the compounds can be characterized in that the molecular weight of R is from 8 to 29 percent by weight of the compound.
While R is a linear hydrocarbon radical having from 12 to 18 carbon atoms for many applications it may be preferred that R be from 16 to 18 carbons. Similarly, while m can be an integer from 8 to 19, for some applications it may be preferred that m at least 10, or even 12 up to 17 or even 15. Likewise, while n can be any integer from 2 to 9, or some applications it may be preferred that n be at least 3, or even 4 up to 8 or even 7.
For many applications it may be desirable to choose R, m and n such that the molecule as a molecular weight of from 600 to 3000 grams per mole, preferably 710 to 1800 grams per mole, more preferably 900 to 1200 grams per mole.
The number of carbons in the R group should be selected so that the molecular weight of R represents from 8 to 29 percent by weight of the compound, more preferably from 12, 15 or even 18 to 27, 25 of even 23 percent by weight of the compound.
The preferred foam control agents for use in the present invention can also be characterized by their cloud point, which can be determined according to ASTM D2024. Preferably the cloud point will be from 10℃ to 30℃, more preferably from 10℃ to 25℃.
As will be readily understood from the formula, the foam control agents for use in the present invention are fatty alcohol initiated alkoxylates. Such materials can be prepared according to methods well known in the art, such as were propoxylating and ethoxylating alcohols of the formula ROH (where R is a linear hydrocarbon radical having from 12 to 18 carbon atoms, as for the foam control agent formula) utilizing well-known alkoxylation catalysts such as double metal cyanide (DMC) or KOH catalysts. Each alcohol product was targeted to consist of between 8 to 19 moles of propylene oxide and 2 to 9 mole of ethylene oxide. The alcohols can be advantageously ethoxylated using purified ethylene oxide at 150-160 ℃ and 40-60 psig in a single, continuous run and then propoxylated using purified propylene oxide at 130-150 ℃ and 40-60 psig in a single, continuous run.
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The foam control agents of the present can be added to the target process mixture (such as fermentation broth) in any amount which is effective to prevent and or break down foam occurring in the mixture. Typically, this may be in an amount from 1 to 5000 ppm, preferably from 5 to 3000 ppm, even more preferably from 10 to 2500 ppm, or even 100 to 2000 ppm by weight of the process mixture.
It has been found that foam control agents for use in the present invention are particularly effective with the process mixture is at a temperature of from about 25℃ to about 45℃.
In another aspect of the present invention, the foam control agent is added to the process mixture as part of a formulation which may comprise, (in addition to the foam control agent described above) one or more of the following components: water, additional foam control agents (including other control agents which fall within the formula described above) , seed oils, mineral oils, wax, surfactants and silicones. Other surfactants which may be added include other materials sold under the Dowfax ^TM-trademark including Dowfax ^TM 146, Dowfax ^TM-144, Dowfax ^TM-142, Dowfax ^TM-122, Dowfax ^TM-123, Dowfax ^TM-114, Dowfax ^TM-111, Dowfax ^TM-117, Dowfax ^TM-163, Dowfax ^TM-105, and Dowfax ^TM-107.
EXAMPLES
To demonstrate the effectiveness of the present invention, a commercial Luria Broth ( “LB broth” ) is used as a standard foaming medium to evaluate foam control agent performance. The fermentation broth solution is prepared by simply dissolving LB Broth Miller in deionized water. LB Broth Miller is supplied by BD Co., Ltd. The LB Broth Miller is reported to contain Tryptone, Yeast extract and Sodium Chloride. The fermentation broth solution is prepared by simply dissolving LB Broth Miller into deionized water in the concentration reported in the tables. No additional microorganism, such as bacteria or fungi or yeast, is added and no sterilization process is applied since the formulation is not intentionally inoculated. Two suppliers of LB broth were utilized for the study. Examples 1-13 and the blanks (unless otherwise noted) were using LB broth from Thermo Fisher Scientific Inc. (lot 200806082408) . Examples 3-2 and Comparative Examples 1-11 and one blank as noted were tested on LB broth from BD Co., Ltd. (lot 5114604) .
The evaluation of foam control agent performance is determined by using Foamscan instrument, which mimics a fermentation tank in an industrial fermentation process by providing a settled airflow speed and temperature. The foaming properties and foam stability are observed and evaluated by optical characteristic (by image analysis) . The volume of foam vs time can be read out by default.
The foam control performance is evaluated by the following procedures:
First 5g (or 2.5 g) of the LB Broth Miller is added into 100 mL deionized water to get the 50 g/L (or 25g/L) fermentation broth solution reported in Table 1.
Then the indicated amount of foam control agent is added into 100 g of the fermentation broth solution to get the formulation for foam testing.
Next the temperature of the Foamscan water bath is set to the indicated temperature (30℃ or 35℃ or 40℃) .
Then 60 mL of the testing solution is injected into a 260 ml sample tube.
When the solution is heated to the target temperature, the test begins by starting the gas (compressed air) bubbling through the solution at a flow rate of 450mL/s.
The foam volume is measured at every 15 seconds up until 300 seconds in total. As the sample tube is 260 ml, foam measurements in excess of 200 ml could not be made.
Table 1 . Innovative examples and comparative examples
The results of this evaluation are presented in Table 2:
Table 2
From the results in Table 2, it can be seen that the innovative examples have comparable or better foam control performance than all comparative examples in LB broth.

Claims

A method for inhibiting the formation of foam in a process comprising the step of adding an effective amount of a foam control agent to a process mixture, which foam control agent comprises a compound that can be represented by the formula

RO (EO) _n (PO) _mH

where R is a linear hydrocarbon radical having from 12 to 18 carbon atoms; EO is ethylene oxide; PO is propylene oxide; n can be any integer from 2 to 9; and m can be any integer from 8 to 19;

wherein the compound is further characterized in that the molecular weight of R is from 8 to 29 percent by weight of the compound.
The method of claim 1 wherein R has from 12 to 18 carbon atoms.
The method of claim 1 wherein the foam control agent has a molecular weight in the range of from 600 to 3000.
The method of claim 3 where the foam control agent has a molecular weight of from 712 to 1800.
The method of claim 1 where the foam control agent has cloud point of from 10 to 30℃.
The method of claim 1 where the process involves fermentation.
The method of claim 6 where the temperature of fermentation process ranges from 25℃ to 45℃
The method of claim 6 where fermentation process is an amino acid fermentation or an enzyme fermentation.
The method of claim 8 where the fermentation products comprises one or more of lysine, MSG and glucose oxidase.
The method of claim 1, wherein the foam control agent is added in an amount from 1 to 5000 ppm by weight of the process mixture.
The method of claim 1 where n is from 4 to 7
The method of claim 1 where m is from 12 to 15
The method of claim 1 wherein the molecular weight of R is from 18 to 23 percent by weight of the foam control agent.
A defoamer formulation comprising a foam control agent, water, and one or more of seed oils, mineral oils, wax, surfactants and silicones, wherein the foam control agent comprises a compound that can be represented by the formula

RO (EO) _n (PO) _mH

where R is a linear hydrocarbon radical having from 12 to 18 carbon atoms; EO is ethylene oxide; PO is propylene oxide; n can be any integer from 2 to 9; and m can be any integer from 8 to 19;

wherein the compound is further characterized in that the molecular weight of R is from 8 to 29 percent by weight of the compound.