• Journal of Life Science
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• v.24 no.10
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• pp.1102-1109
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• 2014

Chungkookjang has several functional properties, such as fibrinolytic activity, anticancer effects, and antioxidant effects. However, children do not like Chungkookjang because of its foul odor. A mixed culture of Bacillus subtilis MC31 and Lactobacillus sakei 383 was used to improve the production of GABA in Chungkookjang and its flavor. Most of the foul odor of Chungkookjang was removed. The slime content and viscosity of Chungkookjang fermented in the mixed culture were similar to those of commercial Chungkookjang when B. subtilis MC31 and Lactobacillus sakei 383 were inoculated in a 1:1 ratio. The maximum GABA content was obtained when Chungkookjang was fermented with B. subtilis MC31 and L. sakei 383, which was fermented at $37^{\circ}C$ for 72 hr. During the period of fermentation, the viable cell number of B. subtilis MC31 reached a peak (log 9.13 CFU/g) at six days, and L. sakei 383 reached a peak (log 6.78 CFU/g) at two days. The moisture, crude ash, crude protein, crude fat, and crude fiber contents were 61.71%, 2.05%, 17.54%, 8.36%, and 1.95%, respectively. The amino-type nitrogen content of Chungkookjang fermented by B. subtilis MC31 and L. sakei 383 was less than Chungkookjang fermented by B. subtilis MC31 alone. The ammonia-type nitrogen and reducing sugar content of the Chungkookjang fermented by B. subtilis MC31 and L. sakei 383 were higher than that of steamed soybean. The glutamic acid and GABA content detected with an amino acid analyzer were 1.40 mg/g and 0.47 mg/g, respectively. These results suggest that fermentation with B. subtilis MC31 and L. sakei 383 in a 1:1 ratio removes more of the foul odor and increases the GABA content compared with single fermentation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.1
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• pp.23-30
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• 2014

The present study investigated the effects of dietary Edwardsiella tarda (E. tarda) specific bacteriophage (phage) and Bacillus subtilis (B. subtilis) mixture on innate immune responses and antibacterial activity of Nile tilapia, Oreochromis niloticus. In a dietary experiment, tilapia were fed the control diet (C), a phage-only supplemented diet (P), a B. subtilis only supplemented diet (B), or a B. subtilis and phage mixed diet (B+P). A respiratory burst and significant increase in lysozyme activity (P<0.05) were noted in the B+P group, as compared to other groups after 4 days of feeding. The B group showed a significant (P<0.05) increase in respiratory burst and lysozyme activity versus the C and P groups, whereas no significant increases (P<0.05) were observed in the P and C groups. $ACH_{50}$ was significantly up-regulated in the B+P group versus other groups after 8 days of feeding (P<0.05). In vivo antibacterial activity was significantly enhanced in the B+P fed group, as compared to other groups (P<0.05) after 7 days of E. tarda challenge. A significant (P<0.05) increase in antibacterial activity was seen in the B group, as compared to C or P groups after 14 days of feeding. These results suggest that a B. subtilis and phage mixture could be utilized as an alternative to antibiotics in the control of fish diseases caused by E. tarda.

• Korean Journal of Microbiology
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• v.36 no.3
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• pp.203-208
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• 2000

A Baczllus circdans KCTC3004 $\alpha$-amylase gene contained in a recombinant plasmid pAL850 was transferred into a new shuttle vector plasmid pALSIlI by ligating linearlzed DNAs of pUC19 and pUB110. B. subtilis RM125 and B. megatenurn ATCC14945 transfonned with pALS111 produced the $\alpha$-amylase substantially Most of the enzyme was produced during the exponential growth period. The maxiinurn activities of the $\alpha$-amylase produced by the Bucillus transformants were compared with that of the B. circulans gene donor strain. The B. subtilis RM125(pALS111) enzyme showed the actlvicy 95 times higher than that of the gene donor cells, followed by the B, nzegaterium ATCC14945(pALSlll) enzyme with activity 34 limes higher than that of the gene donor cells. While E coli secreted about 10% of the produced enzyme, B. subtilis excreted the enzyme inlo the medium wholly and B. megaterirun about 98% ofthe total product. The plasmid pALSI11 was quite stable inB. nzegaterium (92%), inoderately stable in B. subtilis (76%), but was unstable in E. coli (38%). The SDS-PAGE and zymogram of this enzyme produced in E. coli(pALS111), B. subtilis( pALS111) or B. megateril~m (pALS111) indicated a molecular weight of 55,000. The enzymes overproduced in three different host cells hydrolyzed starch to produce mainly maltoaiose and mallooligosaccharides.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.1
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• pp.115-120
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• 2006

To convert the soybean curd residue (SCR) to functional food ingredient, alkaline fermentation of SCR was performed by Bacillus firmus NA-1 and Bacillus subtilis GT-D for 22 hr at $42^{\circ}C$. The micronized full-fat soy flour (MFS) was fortified to reduce the moisture content as well as to supply protein source. The mucilage and flavor productions in the fermented SCR were enhanced by the fortification of $20\%$ MFS. The peptide production from the SCR fermented with B. subtilis GT-D substantially increased when judged by the detectable amount of tyrosine $(480\;mg\%)$. The production of fibrinolytic enzyme was increased by the fermentation for 22 hr, indicating the relative activity of $62\%$ (B. firmus NA-1) and $47\%$ (B. subtilis GT-D), respectively. The SCR fermented by B. firmus NA-1 and B. subtilis GT-D indicated the consistency of $1.95\;Pa{\cdot}s^n\;and\;0.21\;Pa{\cdot}s^n$, respectively. After freeze-drying, the protease activity (615 unit/g) and a-amylase activity (180 unit/g) were obtained from SCR fermented by Bacillus firmus NA-1 and Bacillus subtilis GT-D, respectively.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.7-14
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• 2011

Bacillus subtilis JK-1 showed degradation activity against crude oil, gasoline, kerosene, and light oil, and this strain was used as a crude biosurfactant producing microorganism in this study. To optimize the culture medium for production of crude biosurfactant, the influences of various carbon, nitrogen and mineral sources were assessed. The highest biosurfactant production by B. subtilis JK-1 was observed after 96 h cultivation, containing 1.0% (w/v) soluble starch as a carbon source and 0.5% (w/v) skim milk as a nitrogen source, and carbon to nitrogen concentraion (C/N) ratio was 2.0. For the biosurfactant production 0.1% (w/v) of $KNO_3$ was the most effective mineral source. Comparison of biosurfactant production indicates that B. subtilis JK-1 produces more biosurfactant in the optimum medium established in this study than LB and TSB. Under the optimum medium, the surface tension of culture broth of B. subtilis JK-1 was decreased from 47.3 dyne/cm to 24.0 dyne/cm after cultivation of 48 h.

• Food Science and Preservation
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• v.16 no.4
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• pp.554-561
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• 2009

We investigated the antioxidative effects of solvent extracts of doenjang fermented using Bacillus subtilis DJI (DJI doenjang) in vitro. The solvents used for extraction were ethanol, n-hexane, and water. The antioxidative activities of DJI doenjang solvent extracts were measured by estimation of peroxide value, the presence of linoleic acid level, and nitrite scavenging activity, the Rancimat test, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) free-radical generation, in comparison with the commercial antioxidant butylated hydroxytoluene (BHT). The peroxide value of an ethanol extract was lower than those obtained using n-hexane and water extracts. Furthermore, the peroxide value of the ethanol extract was similar to that obtained after BHT treatment. The nitrite scavenging activity was 23.36% after addition of 600 ppm DJI doenjang ethanol extract, and the DPPH free-radical scavenging activity was 19.06% under same condition, which shows that DJI doenjang ethanol extract exhibited lower antioxidative capacities than did BHT. In the Rancimat test, the ethanol extract (11.20 min induction time), n-hexane extract (7.58 min induction time), and water extract (8.26 min induction time) after treatment with 600 ppm DJI doenjang extracts demonstrated longer induction periods than did BHT (6.94 min). These results indicate that DJI doenjang has potential anti-oxidative activity.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.190-194
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• 2002

Expression of Bacillus subtilis glutamyl-tRNA synthetase (GluRS) in Escherichia coli is lethal for the host, probably because this enzyme misaminoacylates ${tRNA_l}^{Gln}$ with glutamate in vivo. In order to overexpress B. subtilis GluRS, encoded by the gltX gene, in E. coli, this gene was amplified from B. subtilis 168 chromosomal DNA using PCR method and the entire coding region was cloned into a pET11a expression vector so that it was expressed under the control or the T7 Promoter. The resulting recombinant pEBER plasmid was transformed into E. coli Novablue (DE3) bearing the T7 RNA polymerase gene for expression. After IPTG treatment, the overproduced enzyme was purified using ammonium sulfate fractionation, Source Q anion exchange chromatography, Superdex-200 gel filtration, and Mono Q anion exchange chromatography. The purified enzyme yielded 18-fold increase in specific activity over the crude cell extract and its molecular weight was approximately 55 kDa on SDS-PAGE.

• Journal of Ginseng Research
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• v.38 no.3
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• pp.215-219
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• 2014

Background: Biological control of plant pathogens using benign or beneficial microorganisms as antagonistic agents is currently considered to be an important component of integrated pest management in agricultural crops. In this study, we evaluated the potential of Bacillus subtilis strain HK-CSM-1 as a biological control agent against Colletotrichum panacicola. Methods: The potential of B. subtilis HK-CSM-1 as a biological control agent for ginseng anthracnose was assessed. C. panacicola was inoculated to ginseng plants and the incidence and severity of disease was assessed to examine the efficacy of the bacterium as a biological control against C. panacicola. Results: Inoculation of Panax ginseng plants with B. subtilis significantly suppressed the number of disease lesions of C. panacicola and was as effective as the chemical fungicide iminoctadine tris(albesilate). The antifungal activity of B. subtilis against C. panacicola was observed on a co-culture medium. Interestingly, treatment with B. subtilis did not significantly affect the diameter of the lesions, suggesting that the mechanism of protection was through the reduction in the incidence of infection related to the initial events of the infection cycle, including penetration and infection via spore germination and appressorium formation rather than by the inhibition of invasive growth after infection. Conclusion: Our results suggest that B. subtilis HK-CSM-1 can be used as an effective and ecologically friendly biological control agent for anthracnose in P. ginseng.

• 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.