JP4676847B2 - Recombinant microorganism - Google Patents

Description

  The present invention relates to a recombinant microorganism used for producing a useful protein or polypeptide, and a method for producing a protein or polypeptide.

  The industrial production of useful substances by microorganisms includes a wide variety of types including foods such as alcoholic beverages, miso and soy sauce, as well as amino acids, organic acids, nucleic acid-related substances, antibiotics, carbohydrates, lipids, proteins, etc. In addition, its application has been extended to a wide range of fields from foods, medicines, daily necessaries such as detergents and cosmetics to various chemical raw materials.

In industrial production of useful substances by such microorganisms, improvement of productivity is one of the important issues, and breeding of produced bacteria by genetic techniques such as mutation has been performed as a technique. Particularly recently, with the development of microbial genetics and biotechnology, more efficient breeding of production bacteria using genetic recombination techniques has been carried out. Furthermore, in response to the rapid development of genome analysis technology in recent years, attempts have been made to decode genome information of target microorganisms and actively apply them to industry. Industrially useful host microorganisms whose genome information has been disclosed include Bacillus subtilis Marburg No.168 (Non-patent Document 1), Escherichia coli K-12 MG1655 (Non-patent Document 2), Corynebacterium Corynebacterium glutamicum ATCC132032 and the like are mentioned, and strains with improved information have been developed using these genomic information. However, despite the above efforts, the production efficiency has not always been satisfactory.

Nature, 390,249,1997 Science, 277,1453,1997

  The present invention relates to a microorganism in which productivity of a protein or polypeptide is further improved and a method for producing a target protein or polypeptide using the microorganism.

  The present inventors searched for genes that affect the production of useful proteins or polypeptides in various genes encoded on the microbial genome, and after deleting or inactivating a specific gene from the genome. The inventors have found that when a gene encoding a target protein or polypeptide is introduced, the productivity of the target protein or polypeptide is improved as compared with that before deletion or inactivation of the gene.

That is, the present invention relates to Bacillus subtilis genes ansR , degU , gltC , hpr , phoP , purR , pyrR , ykoZ , yobS , yocG , ysmB , yvoA , yvrH , yvzC , ywhA , bofA , ykyB and yuxK , The present invention relates to a recombinant microorganism in which a gene encoding a target protein or polypeptide is introduced into a microorganism strain in which any one or more of genes corresponding to the gene have been deleted or inactivated.

  The present invention also relates to a method for producing a target protein or polypeptide using the recombinant microorganism.

  By using the recombinant microorganism of the present invention, the productivity of the target protein or polypeptide can be improved.

  In the present invention, the identity of the amino acid sequence and the base sequence is calculated by the Lipman-Pearson method (Science, 227, 1435, (1985)). Specifically, it is calculated by performing an analysis with Unit size to compare (ktup) set to 2 using a homology analysis (Search homology) program of genetic information processing software Genetyx-Win (software development).

As the parental microorganism for constructing the microorganism of the present invention, the genes of Bacillus subtilis ansR , degU , gltC , hpr , phoP , purR , pyrR , ykoZ , yobS , yocG , ysmB , yvoA , yvrH , yvzC , ywhA , bofA , Any one having ykyB or yuxK or a gene corresponding to the gene may be used, and these may be wild-type or mutated. Specific examples include bacteria belonging to the genus Bacillus, bacteria belonging to the genus Clostridium , yeast, etc. Among them, bacteria belonging to the genus Bacillus are preferable. Furthermore, Bacillus subtilis is particularly preferred from the viewpoint that whole genome information has been clarified, genetic engineering and genome engineering techniques have been established, and that it has the ability to secrete and produce proteins outside the cells.

Bacillus subtilis genes to be deleted or inactivated in the present invention include ansR , degU , gltC , hpr , phoP , purR , pyrR , ykoZ , yobS , yocG , ysmB , yvoA , yvrH , yvzC , ywhA , bofA, , YkyB and yuxK , or any one or more genes corresponding to the gene.
Table 1 below shows the ansR , degU , gltC , hpr , phoP , purR , pyrR , ykoZ , yobS , yocG , ysmB , yvoA , yvrH , yvzC , ywhA , bofA , ykyB and yuxK gene names and numbers. . These were reported by Kunst et al. (Nature, 390, 249-256, 1997) and published on the JAFAN: Japan Functional Analysis Network for Bacillus subtilis (BSORF DB) (http://bacillus.genome.ad.jp/, 2004). (Updated on March 10) Based on Bacillus subtilis genome data.

  It has the same function as each gene of Bacillus subtilis shown in Table 1, and / or 70% or more, preferably 80% or more, more preferably 90% or more, more preferably 95% in each gene and base sequence of Table 1. As described above, genes derived from other microorganisms, preferably derived from bacteria belonging to the genus Bacillus, having an identity of 98% or more are considered to be genes corresponding to the genes listed in Table 1, and are deleted or not present in the present invention. Included in the gene to be activated.

The number of genes to be deleted or inactivated may be one or more, and it is also possible to combine the deletion or inactivation of genes other than those described above. Furthermore, in addition to the deletion of the above gene group, expression enhancement and function enhancement of other gene groups (for example, prsA gene etc.) can be combined, which is expected to have a greater effect on productivity improvement. The
The gene can be inactivated by a method such as inserting another DNA fragment into the gene or mutating the transcription / translation initiation region of the gene. It is more desirable to physically delete the gene.

The procedure of deletion or inactivation of the gene of the present invention, ansR, degU, gltC, hpr , phoP, purR, pyrR, ykoZ, yobS, yocG, ysmB, yvoA, yvrH, yvzC, ywhA, bofA, ykyB and yuxK In addition to a method of systematically deleting or inactivating a gene corresponding to the gene (target gene), a random gene deletion or inactivating mutation, and then an appropriate method Examples include methods for evaluating protein productivity and performing gene analysis.

  In order to delete or inactivate the target gene, for example, a method by homologous recombination may be used. That is, a circular recombinant plasmid obtained by cloning a DNA fragment containing a part of the target gene into an appropriate plasmid vector is introduced into the parent microbial cell, and the parent gene is homologously recombined in a part of the target gene. It is possible to disrupt and inactivate target genes on the microbial genome. Alternatively, a target gene inactivated by mutation such as base substitution or base insertion, or a linear DNA fragment containing the upstream and downstream regions of the target gene but not the target gene as shown in FIG. Constructed by the method, this is incorporated into the parent microbial cells to cause two crossover homologous recombination at two positions outside the mutation site in the target gene of the parent microbial genome, or upstream and downstream of the target gene. Thus, it is possible to replace the target gene on the genome with a deleted or inactivated gene fragment.

  In particular, when Bacillus subtilis is used as a parental microorganism for constructing the microorganism of the present invention, there have already been several reports on methods for deleting or inactivating a target gene by homologous recombination (Mol. Gen. Genet., 223, 268, 1990, etc.), the host microorganism of the present invention can be obtained by repeating these methods.

  In addition, random gene deletion or inactivation can be achieved by a method of causing homologous recombination similar to the above method using a randomly cloned DNA fragment, or by irradiating a parental microorganism with γ rays, etc. Can also be implemented.

  Hereinafter, the deletion method by the double crossing method using the DNA fragment for deletion prepared by SOE (splicing by overlap extension) -PCR method (Gene, 77, 61, 1989) will be described. The gene deletion method in the present invention is not limited to the following.

  The deletion DNA fragment used in this method is a fragment in which a drug resistance marker gene fragment is inserted between the approximately 1.0 kb fragment adjacent to the upstream of the deletion target gene and the approximately 1.0 kb fragment adjacent to the downstream. . First, an upstream fragment and a downstream fragment of a deletion target gene and three fragments of a drug resistance marker gene fragment are prepared by the first PCR. In this case, for example, upstream of the drug resistance marker gene is formed at the downstream end of the upstream fragment. A primer designed so that a 10-30 base pair sequence on the side and, on the contrary, a 10-30 base pair sequence downstream of the drug resistance marker gene is added to the upstream end of the downstream fragment is used (FIG. 1).

  Next, using the 3 types of PCR fragments prepared in the first round as a template, and performing the second round of PCR using the upstream primer of the upstream fragment and the downstream primer of the downstream fragment, the downstream end of the upstream fragment and the downstream fragment In the drug resistance marker gene sequence added to the upstream end, annealing occurs with the drug resistance marker gene fragment, and as a result of PCR amplification, a DNA fragment in which the drug resistance marker gene is inserted between the upstream fragment and the downstream fragment Can be obtained (FIG. 1).

  When using a chloramphenicol resistance gene as a drug resistance marker gene, for example, using the primer set shown in Table 1, using a general PCR enzyme kit such as Pyrobest DNA polymerase (Takara Shuzo), etc. Protocols. Current Methods and Applications, Edited by BAWhite, Humana Press pp251, 1993, Gene, 77, 61, 1989) etc., by performing SOE-PCR under the usual conditions, etc., DNA fragments for deletion of each gene Is obtained.

  When the DNA fragment for gene deletion thus obtained is introduced into the cell by a competent method or the like, gene recombination occurs in the cell in the homologous region upstream and downstream of the identical deletion target gene. A cell in which a target gene is replaced with a drug resistance gene, or a cell in which a drug resistance gene is inserted into the target gene can be separated by selection with a drug resistance marker (FIG. 1). That is, when a deletion DNA fragment prepared using the primer set shown in Table 2 below is introduced, colonies that grow on an agar medium containing chloramphenicol are isolated, PCR method using the genome as a template, etc. To confirm that the target gene on the genome is replaced with the chloramphenicol resistance gene.

  The target protein or target polypeptide produced using the recombinant microorganism of the present invention is not particularly limited, and examples thereof include various industrial enzymes such as detergents, foods, fibers, feeds, chemicals, medicines, and diagnostics, and bioactive peptides. Industrial enzymes are preferred. In addition, industrial enzymes are classified according to their functions, such as oxidoreductase, transferase, hydrolase, lyase, isomerase, isomerase, and ligase / synthetase. Suitable examples include hydrolases such as cellulase, α-amylase and protease, and transferases such as chloramphenicol acetyltransferase (CAT).

Cellulases include, for example, cellulases belonging to Family 5 in the polysaccharide hydrolase classification (Biochem. J., 280, 309, 1991), and among them, cellulases derived from microorganisms, particularly bacteria derived from the genus Bacillus . As a more specific example, an alkaline cellulase derived from the Bacillus bacterium strain KSM-S237 (FERM BP-7875) comprising the amino acid sequence represented by SEQ ID NO: 2 or a Bacillus bacterium comprising the amino acid sequence represented by SEQ ID NO: 4 Alkaline cellulase derived from KSM-64 strain (FERM BP-2886) or the amino acid sequence and 70%, preferably 80%, more preferably 90% or more, still more preferably 95% or more, particularly preferably 98% or more. A cellulase consisting of an amino acid sequence having identity is exemplified.
In the production of such cellulase, among the Bacillus subtilis genes of the present invention, one of degU , pyrR , yobS , yocG , yvoA , yvrH , yvzC , bofA and ykyB , or a gene corresponding to the gene is deleted or not present. More preferably, an activated microbial strain is used.

Specific examples of α-amylase include α-amylase derived from microorganisms, and particularly liquefied amylase derived from bacteria belonging to the genus Bacillus . More specific examples include alkaline amylase derived from Bacillus genus KSM-K38 strain (FERM BP-6946) consisting of the amino acid sequence represented by SEQ ID NO: 6, and 70%, preferably 80%, more preferably the amino acid sequence. Is an amylase consisting of an amino acid sequence having 90% or more, more preferably 95% or more, particularly preferably 98% or more.
In the production of such α-amylase, among the Bacillus subtilis genes of the present invention, any of ansR , degU , gltC , hpr , phoP , purR , pyrR , ykoZ , yobS , yocG , ysmB , yvoA , ywhA , bofA and ykyB It is more preferable to use a microorganism strain in which a gene corresponding to the gene is deleted or inactivated.

Specific examples of proteases include serine proteases, metal proteases, and the like derived from microorganisms, in particular, Bacillus bacteria. More specific examples include alkaline protease derived from Bacillus clausii KSM-K16 strain (FERM BP-3376) comprising the amino acid sequence represented by SEQ ID NO: 8, and 70%, preferably 80% of the amino acid sequence. More preferred is a protease comprising an amino acid sequence having an identity of 90% or more, more preferably 95% or more, particularly preferably 98% or more.
In the production of such protease, among the Bacillus subtilis gene of the present invention, corresponding degU, pyrR, ykoZ, yobS, ysmB, yvoA, yvrH, yvzC, ywhA, bofA, either ykyB and YuxK, or the gene More preferably, a microbial strain in which the gene is deleted or inactivated is used.

Chloramphenicol acetyltransferase (CAT) is an enzyme that transfers the acetyl group of acetyl-CoA to the 3-position of chloramphenicol. Specifically, CAT derived from Staphylococcus aureus consisting of the amino acid sequence represented by SEQ ID NO: 100, and 70%, preferably 80%, more preferably 90% or more, still more preferably 95% or more, particularly preferably the amino acid sequence. Include proteins having 98% or more identity and having chloramphenicol acetyltransferase activity.
In the production of such CAT, of Bacillus subtilis gene of the present invention, degU, pyrR, yobS, ysmB , yvrH, either bofA and YkyB, or microorganism the gene corresponding to the gene was deleted or inactivated More preferably, the strain is used.

The target protein or polypeptide gene introduced into the microorganism of the present invention is upstream of the control region involved in transcription, translation, and secretion of the gene, that is, the transcription initiation control region including the promoter and transcription start site, and the ribosome binding site. It is desirable that at least one region selected from a translation initiation region including a start codon and a secretory signal peptide region is bound in an appropriate form. In particular, it is preferable that three regions consisting of a transcription initiation control region, a translation initiation control region, and a secretion signal region are combined, and the secretion signal peptide region is derived from a cellulase gene of a bacterium belonging to the genus Bacillus , It is desirable that the start region and the translation start region are 0.6-1 kb region upstream of the cellulase gene and are linked to the target protein or polypeptide gene in an appropriate form. For example, Bacillus (Bacillus) bacteria as described in 2000-210081 and JP 4-190793 Patent Publication JP, i.e. KSM-S237 strain (FERM BP-7875), KSM -64 strain (FERM BP- It is desirable that the transcription initiation regulatory region, the translation initiation region, and the secretory signal peptide region of the cellulase gene derived from 2886) are appropriately combined with the structural gene of the target protein or polypeptide. More specifically, the base sequence of base numbers 1 to 659 of the base sequence shown in SEQ ID NO: 1, the base sequence of base numbers 1 to 696 of the cellulase gene consisting of the base sequence shown in SEQ ID NO: 3, and the base sequence Or a DNA fragment comprising a nucleotide sequence having an identity of 70% or more, preferably 80% or more, more preferably 90% or more, still more preferably 95% or more, particularly preferably 98% or more, or any of the above bases It is desirable that a DNA fragment consisting of a base sequence from which a part of the sequence is deleted is appropriately bound to the structural gene of the target protein or polypeptide. Here, a DNA fragment consisting of a base sequence from which a part of the base sequence has been deleted is a part of the base sequence that has been deleted, but retains functions related to gene transcription, translation, and secretion. Means a DNA fragment.

  The recombinant plasmid of the present invention is obtained by incorporating a recombinant plasmid in which a DNA fragment containing the target protein or polypeptide gene is combined with an appropriate plasmid vector into a host microbial cell using a general transformation method. Microorganisms can be obtained. The recombinant microorganism of the present invention can also be obtained by using a DNA fragment in which an appropriate homologous region with the host microorganism genome is bound to the DNA fragment and directly integrating it into the host microorganism genome.

  Production of the target protein or polypeptide using the recombinant microorganism of the present invention is carried out by inoculating the strain in a medium containing an assimilable carbon source, nitrogen source and other essential components, and cultivating it by a normal microorganism culture method. Then, after completion of the culture, the protein or polypeptide may be collected and purified. And as shown in the Examples described later, the productivity of the target protein or polypeptide is improved as compared with the case of using a microorganism that does not have the gene of the present invention deleted or inactivated. Yes.

  Below, the construction method of the recombinant microorganism of this invention and the production method of cellulase using the said recombinant microorganism are demonstrated concretely.

Example 1
Using ansR-AF and ansR-A / CmR and ansR-B / CmF and ansR-BR primer sets shown in the table using genomic DNA extracted from Bacillus subtilis 168 as a template, ansR gene on the genome A 0.6 kb fragment adjacent to the upstream (A) and a 0.6 kb fragment adjacent to the downstream (B) were prepared. On the other hand, Table 2 shows a recombinant plasmid pCBB31 in which the chloramphenicol resistance gene of plasmid pC194 (J. Bacteriol. 150 (2), 815 (1982)) was inserted into the plasmid pUC18 at the XbaI-BamHI breakpoint. Using the CmF and CmR primer sets, a 1 kb fragment (C) containing a chloramphenicol resistance gene was prepared. Next, the 3 fragments thus obtained (A), (B), and (C) were mixed and used as a template, and SOE-PCR using the primers ansR-AF and ansR-BR in the table was performed to obtain 3 fragments (A ) (C) and (B) were combined in this order to obtain a 2.2-kb DNA fragment (see the figure). Using this DNA fragment, Bacillus subtilis 168 strain was transformed by a competent method, and colonies grown on LB agar medium containing chloramphenicol were isolated as transformants. The genome of the obtained transformant was extracted, and it was confirmed by PCR that the ansR gene was deleted and replaced with a chloramphenicol resistance gene.

Example 2
On the other hand, in the same manner as in Example 1, deletion DNAs prepared using the primer sets of each gene-AF, each gene-A / CmR, each gene-B / CmF, each gene-BR, CmF, and CmR shown in the table Using the fragment, the degU , gltC , hpr , phoP , purR , pyrR , ykoZ , yobS , yocG , ysmB , yvoA , yvrH , yvzC , ywhA, or bofA genes on the genome are deleted and become chloramphenicol resistance genes Each substituted gene deletion strain was isolated.

Example 3
In addition, using the DNA fragments for deletion prepared in the same manner as in Example 2, using the gene-AF, gene-A / Cm2R, gene-B / Cm2F, gene-BR, Cm2F, and Cm2R primer sets shown in the table. A gene deletion strain in which the ykyB gene on the genome was deleted and replaced with a chloramphenicol resistance gene was isolated.

Example 4
Furthermore, it was prepared in the same manner as Example 2 with the primer sets of gene-AF, gene-A / Cm4R, gene-B / Cm4F, gene-BR, gene-A / Cm4F, gene-B / Cm4R shown in the table. using for deletion DNA fragment, YuxK gene on the genome is deleted, the gene deletion strains was replaced by a chloramphenicol resistance gene was isolated respectively.

Example 5
Alkaline cellulase gene derived from Bacillus sp. KSM-S237 strain was added to each gene deletion strain obtained in Example 1-4 and Bacillus subtilis 168 strain as a control (Japanese Patent Laid-Open No. 2000-210081). A recombinant plasmid pHY-S237 in which a DNA fragment (3.1 kb) coding for was inserted into the BamHI restriction site of the shuttle vector pHY300PLK was introduced by the protoplast transformation method. The resulting strain was subjected to shaking culture in 10 mL of LB medium at 30 ° C. overnight, and 0.05 mL of this culture was further added to 50 mL of 2 × L-maltose medium (2% tryptone, 1% yeast extract, 1% NaCl. 7.5% maltose, 7.5 ppm manganese sulfate 4-5 hydrate, 15 ppm tetracycline), followed by shaking culture at 30 ° C. for 3 days. After culturing, the alkaline cellulase activity of the culture supernatant after removing the cells by centrifugation was measured, and the amount of alkaline cellulase secreted and produced outside the cells by the culture was determined. As a result, as shown in Table 3, when each gene-deficient strain was used as the host, a higher secretion of alkaline cellulase was observed compared to the control 168 strain (wild type).

Example 6
Using genomic DNA extracted from Bacillus sp. KSM-K38 strain (FERM BP-6946) as a template, using the primer set of K38matu-F2 (ALAA) and SP64K38-R (XbaI) shown in Table 4 PCR was performed, and the alkaline amylase mature enzyme region 1.6 kb DNA in the base sequence represented by SEQ ID NO: 5 encoding alkaline amylase (JP 2000-184882, Eur. J. Biochem., 268, 2974, 2001) Fragment (D) was amplified. In addition, using the genomic DNA extracted from Bacillus sp. KSM-S237 strain (FERM BP-7875) as a template, the S237ppp-F2 (BamHI) and S237ppp-R2 (ALAA) primer sets shown in Table 4 were used. PCR was performed, and 0.6 kb containing a transcription initiation control region, a translation initiation control promoter region, and a region encoding a secretory signal sequence in the alkaline cellulase gene represented by SEQ ID NO: 1 (Japanese Patent Laid-Open No. 2000-210081) The DNA fragment (E) was amplified. Next, the obtained 2 fragments of (D) and (E) are mixed and used as a template, and SOE-PCR using the S237ppp-F2 (BamHI) and SP64K38-R (XbaI) primer sets shown in Table X is performed. Thus, a 2.2 kb DNA fragment (F) in which the alkaline amylase gene was linked downstream of the transcription initiation regulatory region of the alkaline cellulase gene, the translation initiation regulatory promoter region, and the region encoding the secretory signal sequence was obtained. The obtained 2.2 kb DNA fragment (F) was inserted into the BamHI-XbaI restriction enzyme cleavage point of shuttle vector pHY300PLK (Yakult) to construct alkaline amylase productivity evaluation plasmid pHYK38 (S237ps).

  The constructed alkaline amylase productivity evaluation plasmid pHYK38 (S237ps) was introduced by protoplast transformation method into each gene deletion strain obtained in Example 1-4 and Bacillus subtilis 168 strain as a control. The resulting strain was subjected to shaking culture in 10 mL of LB medium at 30 ° C. overnight, and 0.05 mL of this culture solution was further added to 50 mL of 2 × L-maltose medium (2% tryptone, 1% yeast extract, 1% NaCl, 7.5% maltose, 7.5 ppm manganese sulfate 4-5 hydrate, 15 ppm tetracycline) and shake culture at 30 ° C. for 5 days. After culturing, the alkaline amylase activity of the culture supernatant after removing the cells by centrifugation was measured, and the amount of alkaline amylase secreted and produced outside the cells by the culture was determined. As a result, as shown in Table 5, when each gene deletion strain was used as a host, higher secretion of alkaline amylase was observed as compared to the control 168 strain (wild type).

Example 7
Using genomic DNA extracted from Bacillus clausii KSM-K16 strain (FERM BP-3376) as a template, PCR was performed using a primer set of S237pKAPpp-F and KAPter-R (BglII) shown in Table 6, Alkaline protease (Patent No. 3026111, Kobayashi, T., Hakamada, Y., Adachi, S., Hitomi, J., Yoshimatsu, T., Koike, K., Kawai, S. and Ito, S. (1995) Purification of the alkaline protease from alkalophilic Bacillus sp. KSM-K16. Appl Microbiol Biotechnol., 43 (3): 473-81.) A 1.2 kb DNA fragment (G) containing the sequence and mature enzyme region was amplified. Using genomic DNA extracted from Bacillus sp. KSM-S237 strain (FERM BP-7875) as a template, PCR was performed using the S237ppp-F2 (BamHI) and S237pKAPpp-R primer sets shown in Table 6. Then, a 0.6 kb DNA fragment (H) encoding the transcription initiation control region and the translation initiation control promoter region in the alkaline cellulase gene represented by SEQ ID NO: 1 (Japanese Patent Laid-Open No. 2000-210081) was amplified. Next, the obtained 2 fragments of (G) and (H) are mixed and used as a template, and SOE-PCR using the S237ppp-F2 (BamHI) and KAPter-R (BglII) primer sets shown in Table 6 is performed. As a result, a 1.8 kb DNA fragment (I) in which the alkaline protease signal sequence, the pro sequence and the mature enzyme region were linked downstream of the transcription initiation control region and the translation initiation control promoter region of the alkaline cellulase gene was obtained. The obtained 1.8 kb DNA fragment (I) was inserted into the BamHI-BglII restriction enzyme cleavage point of the shuttle vector pHY300PLK (Yakult) to construct a plasmid pHYKAP (S237p) for evaluating alkaline protease productivity.

  The constructed alkaline protease productivity evaluation plasmid pHYKAP (S237p) was introduced into each gene deletion strain obtained in Example 1-4 and Bacillus subtilis 168 strain as a control by the protoplast transformation method. The bacterial strain thus obtained was subjected to shaking culture in 10 mL of LB medium at 30 ° C. overnight, and 0.05 mL of this culture solution was added to 50 mL of 2 × L-maltose medium (2% tryptone, 1% yeast extract, 1% NaCl. 7.5% maltose, 7.5 ppm manganese sulfate 4-5 hydrate, 15 ppm tetracycline), followed by shaking culture at 30 ° C. for 3 days. After the culture, the alkaline protease activity of the culture supernatant after removing the cells by centrifugation was measured, and the amount of the alkaline protease secreted and produced outside the cells by the culture was determined. As a result, as shown in Table 7, when each gene-deficient strain was used as a host, higher secretory production of alkaline protease was observed compared to the control 168 strain (wild type).

Example 8
PCR was performed using plasmid pC194 as a template and the primer set of SP64sCATm-F and CATm-R (XbaI) shown in Table 8 to amplify a 0.7 kb DNA fragment (J) containing the chloramphenicol acetyltransferase gene. did. Using genomic DNA extracted from Bacillus sp. KSM-S237 strain (FERM BP-7875) as a template, PCR was performed using the S237ppp-F2 (BamHI) and SP64sCATm-R primer sets shown in Table 8. A 0.6 kb DNA fragment (K) encoding a transcription initiation control region, a translation initiation control promoter region, and a part of the signal sequence in the alkaline cellulase gene represented by SEQ ID NO: 1 (Japanese Patent Laid-Open No. 2000-210081). Amplified. Next, the obtained 2 fragments of (J) and (K) are mixed and used as a template, and SOE-PCR using the S237ppp-F2 (BamHI) and CATm-R (XbaI) primer sets shown in Table 8 is performed. Thus, a 1.3 kb DNA fragment (L) in which a chloramphenicol acetyltransferase enzyme region is linked downstream of the transcription initiation control region, translation initiation control promoter region, and part of the signal sequence of the alkaline cellulase gene. Got. The obtained 1.3-kb DNA fragment (L) was inserted into the BamHI-XbaI restriction enzyme cleavage point of shuttle vector pHY300PLK (Yakult) to construct a plasmid pHYCAT (S237pSP64s) for evaluating chloramphenicol acetyltransferase productivity.

  The constructed plasmid chloramphenicol acetyltransferase productivity pHYCAT (S237pSP64s) was introduced into each gene deletion strain obtained in Example 1-4 and Bacillus subtilis 168 strain as a control by the protoplast transformation method. . The resulting strain was subjected to shaking culture in 10 mL of LB medium at 30 ° C. overnight, and 0.05 mL of this culture solution was further added to 50 mL of 2 × L-maltose medium (2% tryptone, 1% yeast extract, 1% NaCl, 7.5% maltose, 7.5 ppm manganese sulfate 4-5 hydrate, 15 ppm tetracycline) and shaking culture at 30 ° C. for 3 days. After culturing, the chloramphenicol acetyltransferase activity of the culture supernatant after removing the cells by centrifugation was measured, and the amount of chloramphenicol acetyltransferase secreted and produced outside the cells by the culture was determined. As a result, as shown in Table 9, when each gene-deleted strain was used as a host, secretion production of chloramphenicol acetyltransferase (CAT) was higher than that of the control 168 strain (wild type). Was recognized.

The preparation of a DNA fragment for gene deletion by SOE-PCR and a method for deleting a target gene (substitution with a drug resistance gene) using the DNA fragment are schematically shown.

Claims (8)

Gene ansR, gltC, hpr, phoP, purR, pyrR, yobS, yocG, ysmB, ywhA, the bofA and B. subtilis strains one of 1 or more on the ykyB is deleted or inactivated, the protein of interest or A recombinant microorganism into which a gene encoding a polypeptide is introduced ,
Three regions consisting of a transcription initiation control region, a translation initiation control region, and a secretion signal region are linked upstream of the gene encoding the protein or polypeptide of interest,
The protein or polypeptide of interest is amylase,
Recombinant microorganism . A recombinant microorganism in which a gene encoding a target protein or polypeptide is introduced into a Bacillus subtilis strain in which any one or more of the genes degU, pyrR, yobS, ysmB, yvzC, bofA, ykyB and yuxK have been deleted or inactivated Because
  Three regions consisting of a transcription initiation control region, a translation initiation control region and a signal region for secretion are linked upstream of the gene encoding the protein or polypeptide of interest,
The protein or polypeptide of interest is a protease,
Recombinant microorganism. A recombinant microorganism in which a gene encoding a target protein or polypeptide is introduced into a Bacillus subtilis strain in which at least one of genes yobS and bofA has been deleted or inactivated,
Three regions consisting of a transcription initiation control region, a translation initiation control region and a signal region for secretion are linked upstream of the gene encoding the protein or polypeptide of interest,
The protein or polypeptide of interest is a cellulase,
Recombinant microorganism. Secretion signal region are those derived from a cellulase gene of Bacillus (Bacillus) bacteria, claims 1-3 transcriptional initiation regulatory region and translational initiation regulatory region is derived from upstream 0.6~1kb region of the cellulase gene The recombinant microorganism according to any one of the above. Three regions comprising a transcription initiation control region, a translation initiation control region, and a secretion signal region are derived from the base sequence of base numbers 1 to 659 of the cellulase gene comprising the base sequence represented by SEQ ID NO: 1, recombinant according to any one of claims 1 to 4 which is a DNA fragment comprising a nucleotide sequence having any 90% identity or more nucleotide sequences or the nucleotide sequence of nucleotide numbers 1 to 696 of cellulase gene of Microorganisms. A method for producing amylase using the recombinant microorganism according to claim 1 . A method for producing a protease using the recombinant microorganism according to claim 2. A method for producing cellulase using the recombinant microorganism according to claim 3.