• Korean Journal of Microbiology
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• v.43 no.4
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• pp.331-336
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• 2007

A bacterium producing the alkaline pretense was isolated from Chungkookjoug, and was identified as Bacillus subtilis JK-1 based on morphological, physiological and biochemical characteristics, as well as phylogenetic analysis using 16S rRNA gene sequence. The optimum pH and temperature of the pretense activity were pH 9.0 and $55^{\circ}C$, respectively. This enzyme was stable at the temperatures $40{\sim}80^{\circ}C$. The maximum alkaline pretense production was obtained when 1.0% (w/v) xylose, 1.0% (w/v) yeast extract and 0.3% (w/v) $CuSO_4$ were used as carbon source, nitrogen source and mineral source. Under the optimal condition, growth of the isolate was reached at stationary phase after 12 hr followed by incubation, the alkaline pretense production reached a maximum level with $16{\sim}20$ hr cultivation.

• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.339-346
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• 2007

The MJP1 bacterial strain, which possesses antifungal activity, was isolated from meju and identified as Bacillus subtilis based on its morphological and biochemical properties, as well as its 16S rRNA sequence. Antimicrobial activity was found against various species of Gram-positive bacteria, yeasts, and molds, including food-spoilage microorganisms. The antifungal activity was found to be stable after heat and proteolytic enzyme treatment, and in the pH range of $6.0{\sim}10.0$. The antibacterial activity was stable in the pH range of $6.0{\sim}10.0$, but about 50% of the activity was lost after 24 hr at $30^{\circ}C$. The antibacterial compound was also inactivated by proteolytic enzyme treatment, indicating its proteinaceous nature. The apparent molecular masses of the partially purified antifungal and antibacterial compounds, as indicated by using the direct detection method in Tricine-SDS-PAGE, were approximately 2.4 kDa and 4.5 kDa, respectively. These studies suggest that B. subtilis MJP1 produces two bacteriocin-like substances with antifungal and antibacterial activities.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.431-439
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• 2014

We report the construction of two Bacillus subtilis expression vectors, pBNS1/pBNS2. Both vectors are based on the strong promoter P43 and the ampicillin resistance gene expression cassette. Additionally, a fragment with the Shine-Dalgarno sequence and a multiple cloning site (BamHI, SalI, SacI, XhoI, PstI, SphI) were inserted. The coding region for the amyQ (encoding an amylase) signal peptide was fused to the promoter P43 of pBNS1 to construct the secreted expression vector pBNS2. The applicability of vectors was tested by first generating the expression vectors pBNS1-GFP/pBNS2-GFP and then detecting for green fluorescent protein gene expression. Next, the mannanase gene from B. pumilus Nsic-2 was fused to vector pBNS2 and we measured the mannanase activity in the supernatant. The mannanase total enzyme activity was 8.65 U/ml, which was 6 times higher than that of the parent strain. Our work provides a feasible way to achieve an effective transformation system for gene expression in B. subtilis and is the first report to achieve B. pumilus mannanase secretory expression in B. subtilis.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.200-204
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• 1991

Certain parts of 36 kinds of plant were extracted by 75% ethanol and water. The extracts were tested their microbial inhibition activities against several food spoilage microorganisms, Bacillus subtilis, Lactobacillus plantarum, Leuconostoc mesenteroides, Pseudomonas fluorescens, Bacillus cereus and Saccharomyces cerevisiae. The ethanol extract of amur cork was shown inhibitory effect on all 6 species of the microorganisms tested. Chinese pepper, sesame cake, gromwell and oak were on 5 species except S. cerevisiae or P. fluorescens and bamboo leaves, lycopi herba, paulownia and rigida were on 4 species. In general amur cork exhibited the strongest inhibition with a few exceptions on certain species. By disc diffusion method, the ethanol extract of leaf mustard showed the highest inhibition effect on B. subtilis, amur cork on L.plantarum, L. mesenteroides and B. cereus, and amur cork and gallnut on P. fluorescens. Mostly the ethanol extracts in comparison with water extracts showed higher inhibition in most of plants but a few exhibited higher in water extracts.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.600-606
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• 2012

A Bacillus sp. that produces fibrinolytic enzyme was isolated from Cheonggukjang, a traditional Korean soybean-fermented food. According to 16S rRNA gene base sequencing, the bacillus was identified as a variety of Bacillus subtilis, and named Bacillus subtilis IDCC 9204. Fibrinolytic enzyme NK-IL9204 was stable up to $60^{\circ}C$ and within pH range of 5-10. Purified NK-IL9204 was detected through fibrin zymography. The molecular weight and isoelectric point of the enzyme were estimated to be 27.7 kDa and 6.7 by SDS-PAGE and 2D electrophoresis, respectively. Its amino acid sequence was similar to that of nattokinase (identities 99.5%) and different from that of nattokinase BPN (identities 86.4%). The plasma fibrinolytic activity of NK-IL9204 was measured by euglobulin clot lysis times (ECLT). The NK-IL9204 was orally administered to SD rats for 3 weeks (1,000 FU/rat/day). The ECLT was significantly shortened by supplementation of NK-IL9204.

• Research in Plant Disease
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• v.12 no.2
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• pp.85-90
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• 2006

Bacillus subtilis BD0310 isolated from tea leaves was used for the development of a biofungicide against Pestalotiopsis longiseta causing gray blight of tea plants. The optimum growth conditions were investigated for the mass cultivation of the microbial agent. The optimum temperature and cultivation time were determined as $12{\sim}24$ hours at $30^{\circ}C$ and the optimum initial pH was pH 7.0 in nutrient broth. Among the tested carbon sources of fructose, galactose, glucose, glycerol, inositol, lactose, maltose, sorbitol and starch, maltose and inositol were found to highly increase antifungal activity of the microbial agent against P. longiseta. Yeast extract and tryptone apparently increased antifungal activity of the microbial agent among the tested nitrogen sources of casein, tryptone, malt extract, yeast extract and $(NH_4)_2SO_4$. The results will make a contribution to mass production of the antagonistic bacterium Bacillus subtilis BD0310 for development of a microbial agent controlling gray blight of tea plants.

• Ocean and Polar Research
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• v.40 no.1
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• pp.23-35
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• 2018

A small cyclopoid copepod M. subtilis (Giesbrecht, 1893 ["1892"]) belonging to the genus Monothula $B{\ddot{o}}ttger-Schnack$ and Huys, 2001 was collected by using $60{\mu}m$ mesh net and firstly recorded in the epipelagic layer of the equatorial Pacific Ocean. We redescribed its morphological characteristics for both female and male, comparing with those of previous studies. Specimens of M. subtilis from the equatorial Pacific Ocean differ from those previously reported by others in terms of the length of the seta G on antenna, being much shorter than setae E and F; in the distal spine on the swimming leg 4, being longer than the length of the third segment on P4. The outer spine of the P3 enp-3 in male is slightly over the tip of conical process. The spine lengths of the distal endopods of P2-P4 for both sexes showed variations among individuals, and the proportions of spine lengths in female are higher than those in male.

• Journal of Life Science
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• v.23 no.4
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• pp.529-536
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• 2013

This study was carried out to investigate the characteristics of white soybean Chungkookjang fermented by Bacillus subtilis D7. The highest germination rate was obtained under $25^{\circ}C$ when water was supplied for 4 days at intervals of 2 hr. The total isoflavone content was 971.3 ${\mu}g/g$ before germination and 1023.8 ${\mu}g/g$ after germination. The amino type- and ammonia type-nitrogen contents of Chungkookjang were proportional to the fermentation time. The pH values of all Chungkookjang soybeans increased up to pH 7.8-8.0 during fermentation. The number of viable cells in all Chungkookjang soybeans increased significantly up to 24 hr. The protease activity of all Chungkookjang soybeans increased up to 30-36 hr. The ${\alpha}$- and ${\beta}$-amylase activities of Chungkookjang fermented by B. subtilis D7 were enhanced with increasing fermentation time. Analysis of the effect of Chungkookjang intake on the liver function of mouse showed that the alkaline phosphatase (ALP) activity and the superoxide dismutase (SOD) activity in the Chungkookjang diet group were markedly higher than those in the control group. The asparatate aminotransferase (AST) activity in the germinated soybean Chungkookjang diet group was higher than that in the nongerminated soybean Chungkookjang diet group. Therefore, Chungkookjang soybeans fermented with B. subtilis D7 can be expected to have an increased content of functional components and improved quality characteristics.

• Journal of Life Science
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• v.23 no.4
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• pp.560-568
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• 2013

Chungkookjang was fermented by B. subtilis MC31, a ${\gamma}$-amino butyric acid (GABA) producing microorganism. The characteristics of Chungkookjang were investigated while fermenting. Twenty four amino acids were detected in Chungkookjang, leucine was the highest of them all. Total cell populations of B. subtilis MC31 phase were between log $9.52{\pm}0.5$ ~ log $9.049{\pm}0.5$ CFU/g at stationary phase. Contents of moisture, crude ash, crude protein, crude lipid and crude fiber are $61.07{\pm}0.01%$, $1.52{\pm}0.01%$, $17.66{\pm}0.04%$, $8.96{\pm}0.03%$ and 2.61%, respectively. Contents of ammonia type nitrogen, amino type nitrogen and reducing sugar were increased during fermentation at $40^{\circ}C$ for 72 hr, however those of titratable acidity and total sugar were decreased. pH was slowly alkalized during fermentation. Viscous substance and protease contents in Chungkookjang were $4.7{\pm}0.05%$ and $0.519{\pm}7.36$ g/l, apiece. When the fibrin plate and Robbin method for fibrinolytic activity were applied, B. subtilis MC31 showed high activity. These results suggested that B. subtilis MC31 is suitable to be used as a starter to enhance the quality of Chungkookjang.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1462-1470
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• 2022

Natural antimicrobial substances are needed as alternatives to synthetic antimicrobials to protect against foodborne pathogens. In this study, a bacteriocin-producing bacterium, Bacillus subtilis HD15, was isolated from doenjang, a traditional Korean fermented soybean paste. We sequenced the complete genome of B. subtilis HD15. This genome size was 4,173,431 bp with a G + C content of of 43.58%, 4,305 genes, and 4,222 protein-coding genes with predicted functions, including a subtilosin A gene cluster. The bacteriocin was purified by ammonium sulfate precipitation, Diethylaminoethanol-Sepharose chromatography, and Sephacryl gel filtration, with 12.4-fold purification and 26.2% yield, respectively. The purified protein had a molecular weight of 3.6 kDa. The N-terminal amino acid sequence showed the highest similarity to Bacillus subtilis 168 subtilosin A (78%) but only 68% similarity to B. tequilensis subtilosin proteins, indicating that the antimicrobial substance isolated from B. subtilis HD15 is a novel bacteriocin related to subtilosin A. The purified protein from B. subtilis HD15 exhibited high antimicrobial activity against Listeria monocytogenes and Bacillus cereus. It showed stable activity in the range 0-70℃ and pH 2-10 and was completely inhibited by protease, proteinase K, and pronase E treatment, suggesting that it is a proteinaceous substance. These findings support the potential industrial applications of the novel bacteriocin purified from B. subtilis HD15.