• Journal of Life Science
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• v.23 no.1
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• pp.102-109
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• 2013

To isolate GABA-producing microorganisms, 1,500 strains were isolated from different Chungkookjang samples and screened. From these strains, 20 were selected for further analyses based on a protease and slime-producing activity test. The MC 31 strain showed the highest GABA concentration in Chungkookjang and was used in this study. MC 31 was identified as Bacillus subtilis by an API 50CHB kit and 16S rDNA sequences analysis and named as B. subtilis MC 31. B. subtilis MC 31 showed exponential growth up to 12 hours at $37^{\circ}C$ in LB broth, and it reached a stationary phase after 24 to 36 hours of incubation. B. subtilis MC 31 showed maximum GABA content at 72 hours after incubation at $40^{\circ}C$.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.354-361
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• 2008

A novel bacterium isolated from Cheonggukjang was identified as a glutamate-dependent Bacillus subtilis HA with 98.3% similarity to Bacillus subtilis Z99104. Optimization of poly-$\gamma$-glutamic acid ($\gamma$-PGA) production by modulating fermentation factors including carbon sources, nitrogen sources, inorganic salts and fermentation time was investigated. Optimum culture broth for $\gamma$-PGA production consisted of 3% glutamate, 3% glucose and various salts, resulting in the PGA production of 22.5 g/L by shaking culture for 72 hr at $37^{\circ}C$. Average molecular weight of $\gamma$-PGA was determined to be 1,220 kDa through MALLS analysis. The $\gamma$-PGA solution showed a typical pseudoplastic flow behavior, and a great decrease in consistency below pH 6.0 regardless of the same molecular weight of $\gamma$-PGA. The molecular weights of isolated $\gamma$-PGA were drastically decreased by heat treatment in various acidic conditions, resulting in different hydrolysis of $\gamma$-PGA. The consistency of $\gamma$-PGA solution was greatly decreased with increase heating time in acidic conditions.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.348-355
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• 1991

DNA segment encoding $\beta$-1, 4-glucanase of Bacillus subtilis was fused in frame to mouse $\alpha$-amylase signal sequence behind the alcohol dehydrogenase isoenzyme I gene (ADHI) promoter of the yeast expression vector pMS12. To enhance the expression level of the $\beta$glucanase gene in yeast, transcription terminator sequence iso-1-cytochrome c gene (CYCI) was inserted into the recombinant plasmid. The transformants harbouring such recombinant plasmids secreted $\beta$-glucanase into the culture medium. The expresstion level of the $\beta$-glucanase gene was increased about 2-fold caused by inserting the terminator. The amount of the secreted $\beta$-glucanase in culture medium was approximately 60% of the total quantity synthesized.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.349-354
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• 1998

The protease produced by Bacillus subtilis YG-95 was purified by precipitating with ammonium sulfate, DEAE-sepharose 6B and Sephadex G-100 column chromatogtaphies and its purified enzymological characteritics were investigated. The molecular weight of purified protease was estimated about 43kilodalton by SDS PAGE The optimum pH and temperature for the purified protease activity were pH 10.0 and $55^{\circ}C$, respectively. The enzyme was stable in broad range of pH 5.0 to 12.0. and at the below $45^{\circ}C$. The purified enzyme activty was inhibited by $Fe^{3+}$ and $Al^{3+}$. The activity was significantly inhibited more than 80% by O-Phenanthroline, PMSF and SDS. The $K_m$ value of the purified enzyme against Soy Protein Isolate as a substrate was 1.28 mg/ml.

• Journal of Life Science
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• v.25 no.6
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• pp.680-685
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• 2015

Previously, cellulase and xylanase producing microorganism, Bacillus subtilis NC1, was isolated from soil. Based on the 16S rRNA gene sequence and API 50 CHL test the strain was identified as Bacillus subtilis, and named as B. subtilis NC1. We cloned and sequenced the genes for cellulase and xylanase. Plus, the deduced amino acid sequences from the genes of cellulase and xylanase were determined and were also identified as glycosyl hydrolases family (GH) 5 and 30, respectively. In this study to optimize the medium parameters for cellulase production by B. subtilis NC1 the RSM (response surface methodology) based on CCD (central composite design) model was performed. Three factors, tryptone, yeast extract, and NaCl, for N or C source were investigated. The cellulase activity was measured with a carboxylmethyl cellulose (CMC) plate and the 3,5-dinitrosalicylic acid (DNS) methods. The coefficient of determination (R²) for the model was 0.960, and the probability value (p=0.0001) of the regression model was highly significant. Based on the RSM, the optimum conditions for cellulase production by B. subtilis NC1 were predicted to be tryptone of 2.5%, yeast extract of 0.5%, and NaCl of 1.0%. Through the model verification, cellulase activity of Bacillus subtilis NC1 increased from 0.5 to 0.62 U/ml (24%) compared to the original medium.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.527-533
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• 2008

For preparation of high quality kochujang by the traditional fermentation method, 4 types of kochujang were prepared with brick- or grain-shaped meju fermented with different strains (Aspergillus sojae, Aspergillus oryzae+Bacillus subtilis). After 100 days of fermentation at $25^{\circ}C$, the moisture, pH, salt, and ethanol content of kochujang were 40.52-43.20%, 4.71-4.82, 8.7-9.1%, and 0.75-0.94%, respectively, showing slight differences according to the strains and shapes of meju. Titratable acidities were slightly increased for up to 60 days of fermentation. The amino-type nitrogen content of kochujang prepared with brick-shaped meju (A. oryzae+B. subtilis) was the highest (164.20 mg%) among all of the kochujang types. The redness (a) value of kochujang prepared with brick-shaped meju (A. sojae) were higher (19.08) than those of other treatments (18.37-18.59). Sensory evaluation of kochujang prepared with grain-shaped meju (A. sojae) showed the highest scores for color and overall acceptability, 'at $6.43{\pm}1.87$ and $6.29{\pm}1.44$, respectively. It was estimated that high quality kochujang could be made by using meju fermented with selected strains.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.395-402
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• 2001

A fusant FG-21 was selected on the basis of higher ${\gamma}-GTP$ activity following fusion process between SM-2 and SM-10 of Bacillus subtilis mutants. ${\gamma}-GTP$ activity of the mutant FG-21 was increased up to 612 U/mL when grown for 36 hr at $37^{\circ}C$ in culture media containing 1% glycerol 1% glycerol, 1% peptone, 0.1% citric acid, 5 mM $K_2HPO_4$, 1 mM $FeCl_3$, 1 mM $MgCl_2$, 1 mM $NH_4Cl$, pH 7.0. In fusnat FG-21, the ratio of protein to total sugar contents for biopolymer A was 38 to 59. for biopolymer B from parental strains it was 19 to 78. Fructose contents determined by HPLC were $573.7\;\mu\textrm{g}/mg\;and\;764.4\;\mu\textrm{g}/mg$ for biopolymer A and B, respectively. And glutamic acid content were $163.7\;\mu\textrm{g}/mg\;and\;94.6\;\mu\textrm{g}/mg$ for biopolymer A and B, respectively. In fusant FG-21, the ratio of fructose to glutamic acid contents for biopolymer A was 78 to 22. For biopolymer B from parental strains it was 89 to 11.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.655-658
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• 2008

Although arabinose isomerase (E.C. 5.3.1.4), a commercial enzyme for edible tagatose bioconversion, can be expressed in an Escherichia coli system, this expression system might leave noxious by-products in food. To develop an eligible tagatose bioconversion with food-safe system, we compared the tagatose production activity of immobilized arabinose isomerase expressed in Bacillus subtilis (a host generally recognized as safe) with that of the enzyme expressed in E. coli. A 48% increase in tagatose production (4.3 g tagatose/L at $69.4\;mg/L{\cdot}hr$) was found using the B. subtilis-expressed immobilized enzyme system, compared to the E. coli-expressed enzyme system (2.9 g tagatose/L). The increased productivity with safety of the B. subtilis-expressed arabinose isomerase suggests that it is a more eligible candidate for commercial tagatose production.

• Journal of Life Science
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• v.28 no.6
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• pp.697-707
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• 2018

The aim of this study was to investigate the potential effects of extracts from silkworm (Bombyx mori L.) that was fermented with Bacillus subtilis KACC 91157 at the levels of 1%(v/w), 2.5%(v/w), and 5%(v/w) in alcohol-fed rats. Sprague-Dawley rats were divided into seven groups: normal group (N), alcohol treated group (C), silymarin treated group (PC, positive control), 5% silkworm powder treated group (SP5), 1% Bacillus subtilis-fermented silkworm powder treated group (BSP1), 2.5% BSP treated group (BSP2.5), and 5% BSP treated group (BSP5). The activities of AST, ALT, ALP, and LDH in the serum and the triglyceride concentrations in the liver and serum were increased by alcohol feeding but were reduced in the BSP5 group. In addition, the contents of total lipids, free fatty acids, and total cholesterol were increased in the alcohol-fed group but were reduced in the BSP5 group. The activities of ADH, ALDH and ADH, ALDH protein levels in the liver were increased in the BSP5 group. The TBARS contents in the liver, serum, liver mitochondria, and liver microsomes were slightly decreased in the BSP5 group compared to the C group. The hepatocytes in alcohol-fed rats contained numerous large droplets; however, BSP5 treatment prevented alcohol-induced lipid droplet accumulation in the hepatocytes. Based on these results, extracts from Bacillus subtilis-fermented silkworm (Bombyx mori L.) have significant potential for development into a functional health food that can improve alcoholic fatty liver conditions.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.223-229
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• 1988

Bacillus subtilis K-4-3, which produces considerable amount of $\beta$-glucanase was selected among extracellular $\beta$-glucanase-producing bacteria isolated from soil. $\beta$-glucanase was purified by ammonium sulfate fractionation, Sephadex G-100 gel filtration and DEAE-sephacel ion exchange chromatography. The purified enzyme revealed a single band by polyacrylamide gel electrophoresis and SDS-polyacrylamide gel electrophoresis. Its molecular weight was estimated to be 17000 dalton by SDS-polyacrylamide gel electrophoresis. The optimum pH and temperature of the purified $\beta$-glucanase were 7.0 and $50^{\circ}C$, respectively. The enzyme was strongly inhibited by 1.0mM of $Fe^{3+}$, and activated by 1.0mm of $Li^{}47+$. The absence of glucose after thin layer chromatography of reaction products revealed that the purified enzyme contains no cellobiase or laminarinbiase activity. The loberation of ki, tri-and tetra-saccharide as reaction products can be explained by endoaction of the enzyme.