• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.507-513
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• 2017

Bacillus subtilis spores can be used for protein display to engineer protein properties. This method overcomes viability and protein-folding concerns associated with traditional protein display methods. Spores remain viable under extreme conditions and the genotype/phenotype connection remains intact. In addition, the natural sporulation process eliminates protein-folding concerns that are coupled to the target protein traveling through cell membranes. Furthermore, ATP-dependent chaperones are present to assist in protein folding. CotA was optimized as a whole-cell biocatalyst immobilized in an inert matrix of the spore. In general, proteins that are immobilized have advantages in biocatalysis. For example, the protein can be easily removed from the reaction and it is more stable. The aim is to improve the pH stability using spore display. The maximum activity of CotA is between pH 4 and 5 for the substrate ABTS (ABTS = diammonium 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate). However, the activity dramatically decreases at pH 4. The activity is not significantly altered at pH 5. A library of approximately 3,000 clones was screened. A E498G variant was identified to have a half-life of inactivation ($t_{1/2}$) at pH 4 that was 24.8 times greater compared with wt-CotA. In a previous investigation, a CotA library was screened for organic solvent resistance and a T480A mutant was found. Consequently, T480A/E498G-CotA was constructed and the $t_{1/2}$ was 62.1 times greater than wt-CotA. Finally, E498G-CotA and T480A/E498G-CotA yielded 3.7- and 5.3-fold more product than did wt-CotA after recycling the biocatalyst seven times over 42 h.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.5
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• pp.539-543
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• 1992

This study was carried out to investigate the antimutagenic affect of crude and heated comfrey extract on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), benzo${(\alpha)}$pyrene (B${(\alpha)}$P) and 3-amino-1, 4-dimethyl-5H-pyri-do [4,3-b] indole (Trp-P-1). In spore rec-assay using Bacillus subtilis $H17(rec^+)$ and $M45(rec^-),$ crude comfrey extract showed strong antimutagenic effects on MNNG in the concentration of $40{\mu}l/disc$(p<0.01). In the Ames test using Salmonella typhimurium TA98 and TA100, the crude comfrey extract suppressed about 43% and 52% in the mutagenesis induced by $B{(\alpha)}P.$ However, the heated comfrey extract strongly suppressed about 75% and 76% in the mutagenesis in Salmonella typhimurium TA98 and TA100 induced by Trp-P-1(p<0.01).

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.880-886
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• 1995

Antimutagenic effects of boiled water extract and tannin from persimmon leaves were studied by using Ames test, spore rec assay and SOS chromotest. Strong antimutagenic activities toward aflatoxin B1(AFB1), dimethyl-aminobiphenyl(DMAB), N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and 4-nitroquinoline-1-oxide(4-NQO) were observed when boiled water extract and tannin from the persimmon leaves were added in the Salmonella typhimurium TA 100. In spore rec assay using Bacillus subtilis H17($rec^{+}$) and M45($rec^{-}$), boiled water extract and tannin from the persimmon leaves considerably inhibited the mutagenesis induce by MNNG. In SOS chromotest using Escherichia coli PQ37, these samples also exhibited strong antimutagenic activity toward 4-NQO. The tannin was more effective than boiled water extract of persimmon leaves in the antimutagenicity tests.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.21-24
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• 1991

The promoter isolated from an alkali-tolerant Hwillus sp. chromosomal DNA was subcluned. The activity of promoter in B, subtilis and alkali-tolerant Bacillus sp. began to increase at the early stage. of spore formation. In the presence of 1% glucose, the promotcr activity repressed and was recovered by ;tddition of c-GMP in the medium.

• Microbiology and Biotechnology Letters
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• v.28 no.4
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• pp.219-222
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• 2000

To produce and utilize microbial cyclomaltodextrinase being industrially useful, we isolated an alkalophilic Bacillus strain from soil which was capable of degrading cyclodextrins. The newly isolated strain was aerobic, gram-positive, spore-forming, motile, rod shape(0.2~0.4$\times$1.4~4.4 $\mu\textrm{m}$), and 35.8 mol% of DNA base composition. Based on its morphological, phisiological, and biochemical properties, it was identified as alkalophilic Bacillus sp. KJ-133 and cultivated well in the ranges of $30~40^{\circ}C$ and pH 8.0~9.0 . The cyclomaltodextrinase of the strain showed maximal production after 48h of cultivation at $37^{\circ}C$, and the activity was inhibited by Ag2+, Hg2+, Cu2+, and p-chloromercuribenzoate.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1597-1604
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• 2012

Genus Bacillus is a spore-forming bacterium that has unique properties in cell differentiation, allowing the forming of spores in stress conditions and activated in the vegetative cell, with suitable environments occurring during the life cycle acting as a trigger. Their habitat is mainly in soil; thus, many species of Bacillus are associated with plants as well as rhizosphere bacteria and endophytic bacteria. Signal transduction is the principal mechanism of interactions, both within the cell community and with the external environment, which provides the subsequent functions or properties for the cell. The antimicrobial compounds of Bacillus sp. are potentially useful products, which have been used in agriculture for the inhibition of phytopathogens, for the stimulation of plant growth, and in the food industry as probiotics. There are two systems for the synthesis of these substances: nonribosomal synthesis of cyclic lipopeptides (NRPS) and polyketides (PKS). For each group, the structures, properties, and genes of the main products are described. The different compounds described and the way in which they co-exist exhibit the relationship of Bacillus substances to plants, humans, and animals.

• The Korean Journal of Food And Nutrition
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• v.12 no.1
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• pp.1-6
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• 1999

The strain isolated for making chungkuk-jang was Bacillus subtilis which formed sport with 98% ratio. Logarithmical culture was inoculated(1,000 CF/g) to the steamed soybeans and at th optimum fer-mentation conditions(4$0^{\circ}C$, RH 90%) fermentation progressed very rapidly and synchronously. Fermen-tation time was 24 hours on the optimum fermentation conditions. During activated fermentation chun-gkuk-jang's aroma and flavor created. After finishing the fermentation the spore forming ratio was 95% and replenishment was not occured easily during aging at the below 5$^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.543-547
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• 1991

An alkalophilic microorganism, SH-8, was isolated from soil samples. It was a Grampositive, catalase-positive, spore-forming and motile rod which was capable of growth in aerobic condition at the initial pH 9.0 or above up to 11.0 and between 15 and $42^{\circ}C$ The characteristics of this strain resembled those of the Bacillus group of bacteria. The mutant, Bacillus sp. SH- 8M, was selected from Bacillus sp. SH-8 by U.V. mutagenesis and was able to grow at pH 6.9 up to 11.0. These two strains will be suitable for the comparative study on growth and enzyme production at various pH conditions.

• Microbiology and Biotechnology Letters
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• v.25 no.5
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• pp.527-533
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• 1997

From apple skin, we isolated a bacterial strain which strongly inhibited the growth of apple white rot fungus, Botryosphaeria dothidea. The isolated strain, designated as SS279, was identified to be the genus Bacillus. The antifungal activity of Bacillus sp. SS279 was found in the culture filtrate. The production of antifungal substances occurred during logarithmic phase and was the highest when cultures reached the stationary growth phase. The optimum ranges of temperature and pH for its production were 25-30$\circ$C and 4.5-9.0, respectively. The culture filtrate of Bacillus sp. SS279 exhibited a strong inhibitory effect on the spore germination and germ tube elongation of B. dothidea. Autoclaved culture filtrate of Bacillus sp. SS279 showed only a slight decrease in antifungal activity, indicating that the Bacillus sp. SS279 produce heat-stable antifungal substances. In in vivo bioassay, Bacillus sp. SS279 also showed antagonistic activity against apple white rot caused by B. dothidea.

• Journal of Dairy Science and Biotechnology
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• v.39 no.3
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• pp.87-93
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• 2021

This study analyzed and compared growth characteristics under large-scale fermentation at 35℃ of three microorganisms with the ability to reduce odor-producing substances in livestock. The three microorganisms (Bacillus subtilis FWC1, Bacillus amyloliquefaciens NAAS1, and Pichia farinosa NAAS2) evaluated in this study have been proven effective in reducing odor-inducing substances. Bacillus subtilis FWC1 exhibited the highest viable cell count when using 2% maltodextrin as carbon source, 0.05% soy-peptone as nitrogen source, and 0.3% yeast extract. The optimum media composition for B. amyloliquefaciens NAAS1 was 1.2% modified-starch with 0.8% yeast extract. The spore formation rate in the mass production of the Bacillus strains was over 90%, indicating that optimal growth medium compositions have been identified. In the case of P. farinosa NAAS2, our optimized growth medium [2% (w/v) glucose and 1% (w/v) yeast extract] improved biomass production.