• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.447-453
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• 2007

With a broad objective for the development of microbial based fertilizers, a total of 373 strains were isolated from rhizoplane and rhizosphere of pepper, tomato, lettuce, pasture, and grass. The efficacy of the isolates to augument overall plant growth was evaluated. After screening for their plant growth promotion and antagonistic properties in vitro efficient strains were further selected. The most efficient strains was characterized by 16S rRNA gene sequences and biochemical techniques and was designated as Bacillus subtilis S37-2. The strains facilitated plant growth and inhibited the plant phathogenic fungi such as Fusarium oxysporum (KACC 40037, Rhizoctonia solani (KACC 40140), and Sclerotinia sclerotiorum (KACC 40457). Pot based bioassay using lettuce as test plant was conducted by inoculating suspension ($10^5$ to $10^8cells\;mL^{-1}$) of B. subtilis S37-2 to the rhizosphere of lettuce cultivated in soil pots. Compared with non-inoculated pots, marked increase in leaf (42.3%) and root mass (48.7%) was observed in the inoculation group where the 50ml of cell mixture ($8.7{\times}10^8cells\;ml^{-1}$) was applied to the rhizosphere of letuce either once or twice. Antagonistic effects of B. subtilis S37-2 strain on S. sclerotiorum (KACC 40457) were tested. All the tested lettuce plants perished after 9 days in treatment containing only S. sclerotiorum, but only 17% of lettuce was perished in the inoculation plot. B. subtilis grew well in the TSB culture medium. The isolates grew better in yeast extracts than peptone and tryptone as nitrogen source. The growth rate was 2~4 times greater at $37^{\circ}C$ as compared with $30^{\circ}C$ incubation temperature. B. subitlis S37-2 produced $0.1{\mu}g\;ml^{-1}$ of IAA (indole 3-acetic acid) in the TSB medium containing L-tryptophan($20mg\;L^{-1}$) in 24 hours.

• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.12-18
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• 2017

Microbial strains exhibiting proteolytic activity were isolated from kimchi, one of traditional fermented foods in Korea. Eight strains formed clear zones around their colonies when grown on TSA plates supplemented with skim milk. MBE/L865 exhibited 2.6-fold higher protease activity than that of control strain (Bacillus subtilis KCTC13112). MBE/L865 was identified as B. subtilis and deposited in the Korean Collection for Type Cultures under the accession number of KCCM43059. The optimum growth conditions for B. subtilis KCCM43059 were determined to be $37^{\circ}C$ and pH 8. The strain showed maximum protease activity ($429.37{\pm}18.65U/mg$ protein) at $60^{\circ}C$ and pH 6. Further, B. subtilis KCCM43059 had a higher salt (NaCl) tolerance than that of the control strain.

• Journal of Life Science
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• v.25 no.11
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• pp.1319-1323
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• 2015

Aquaculture continues to be an ever-growing sector. However, high-density farming increases disease outbreaks due to deteriorating water quality and internal stress. To prevent disease, the most common method chemotherapy is using antibiotic administration. In this study, probiotic bacteria were isolated from Korean traditional foods, such a Gochu pickle and cutlassfish salted seafood. Various bacteria were isolated, and their 16S rDNA sequences were analyzed. The antimicrobial activities of four isolates from Gochu pickle and seven isolates from cutlassfish salted seafood were assayed, in addition to the antibacterial activity of culture pellet and supernatant. The antibacterial activity of the pellet was higher than that of the supernatant. Isolate JKM-2 showed the highest antibacterial activity against Streptococcus iniae (43 mm), S. parauberis (40 mm), S. mutans (35 mm), and Vibrio vuinificus (26.5 mm). The sequences of the isolated strains were compared with those of Bacillus subtilis (97.71%), B. tequilensis (97.71%), Brevibacterium halotolerans (97.71%), B. subtilis (97.63%), B. subtilis (97.63%), B. mojavensis (97.54%), B. vallismortis (97.46%), B. nanillea (97.45%), B. methylotrophicus (97.37%), and B. ssiamensis (97.37%). Future through analysis and new strains confirmed the bacterial cell material investigation of JKM-3, and to ensure sufficient stability, it is desired to verify the utility value as a substitute material for antibiotics by application to the form of the industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1382-1388
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• 2008

Antimicrobial activities of green tea extracts used for coarse tea were investigated by disc diffusion method using eight different bacteria. Among the green tea extracts, the 70% ethanol extract demonstrated the strongest antimicrobial activities against Vibrio parahemolyticus (V. parahemolyticus) and Staphylococcus aureus (S. aureus) and thus was further fractionated. Among these fractions, the ethyl acetate fraction showed the strongest antimicrobial activities against V. parahemolyticus, S. aureus, Bacillus subtilis (B. subtilis), and Streptococcus mutans (S. mutans). These activities exceeded that of all extracts and fractions tested in this study. Interestingly, although green tea extracts showed significant antimicrobial activity against Micrococcus luteus (M. luteus), once fractionated, the ethyl acetate fraction did not show any antimicrobial activity against M. luteus. MICs of the ethyl acetate fraction were $5\;\;{\mu}L$/disc against B. subtilis and $3\;{\mu}L$/disc against S. aureus, S. mutans and V. parahaemolyticus. 90% inhibition of B. subtilis was observed with 0.05% ethyl acetate fraction but S. mutans needed over 0.1% ethyl acetate fraction to exhibit the same inhibition as B. subtilis. Antimicrobial activities of ethyl acetate fractions were reduced around 10% by thermal treatment at $121^{\circ}C$ for 20 min. All the results suggest that the 70% ethanol extract as well as the ethyl acetate fraction from green tea used for coarse tea could be further developed into a natural antimicrobial agent.

• Korean Journal of Microbiology
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• v.37 no.4
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• pp.253-258
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• 2001

A Bacillus circulans KCTC3004 $\beta$-1,3-glucanase gene contained in a recombinant plasmid pLM460 derived from subcloning the original recombinant plasmid pLM530 was trasferred into a new shuttle vector plasmid pLMS1180 by ligating linearized DNAs of pLM460 and pUB110. B. subtilis RM125 and B. megaterium ATCC14945 transformed with pLMS1180 produced the $\beta$-1,3-glucanase substantially. Most of the enzyme was produced during the exponential growth period. The maxium activities of the $\beta$-1,3-glucanase produced by the Bacillus transformants were compared with that of the B. circulans gene donor strain. The B. subtilis RM125 (pLM1180) enzyme showed the activity 14 times higher than that of the gene donor cells, followed by the B. megaterium ATCC14945 (pLMS 1180) enzyme with activity 5 times higher than that of the gene donor cells. While E. coli secreted about 7% of the produced enzyme, B. subtilis excreted the enzyme into the medium wholly and B. megaterium about 97% of the total product. The SDS-PAGE of this enzyme produced in E. coli (pLMS1180), B subtilis (pLMS1180) or B. megaterium (pLMS1180) indicated a molecular weight of 38,000. The enzymes overproduced in three different host cells hydrolyzed laminarin to produce mainly laminaribiose, laminaritriose, and laminarioligosaccharides. The plasmid pLMS1180 was stable in B. megaterium, E. coli, but was unstable in B. subtilis.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.185-193
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• 2016

A novel proteolytic bacterium was isolated from soil at Yeungnam University, South Korea. The strain, named FBL-1, was rod-shaped with a smooth surface. Biolog and API 50CHB test results revealed that strain FBL-1 was a Bacillus species. Based on 16S rDNA sequencing and chemotaxonomic characterization, the strain was identified as Bacillus subtilis because it had the highest homology with Bacillus subtilis subsp. subtilis NCIB 3610 (99.5%). In liquid culture at 37℃ with shaking at 200 rpm, fructose and yeast extract were found to be the best carbon and nitrogen sources, respectively, for cell growth and protease production. The highest protease activity (451.640 U/ml) was obtained when the strain was cultured in medium containing 20 g/l of fructose and 5 g/l of yeast extract. Although further studies are needed to characterize the protease and enhance its activity, the newly isolated protein-degrading B. subtilis FBL-1 can be applicable for the production of peptides and for the degradation of proteins in various industries.

• Journal of Life Science
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• v.12 no.1
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• pp.77-86
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• 2002

Chitin, a $\beta$-1,4 polymer of N-acetyl-D-glucosamine, is one of the most abundant organic compounds in nature. Chitinase (EC 3.2.1.14) is an enzyme that degrades chitin to chito-oligosaccharides, diacetyl rhitobiose and N-acetyl-D-glucosamine. An extracellular chitinase-producing bacterial strain was isolated from soil and named to as Bacillus subtilis JK-56. Optimum culture condition of B. subtilis JK-56 for the production of chitinase was 1% chitin, 0.5% polypepton, 0.1% KCl, 0.05% MnS $O_4$.4$H_2O$, 37$^{\circ}C$, initial pH 7.0 and 40 hour culture time. When B. subtilis JK-56 was grown in the optimum medium, one major active band and two minor active bands were detected by native-PAGE and active staining of the gel. Among them, the major band was purified from the culture supernatant by 70% ammonium sulfate precipitation and native-PAGE with BIO-RAD Model 491 Prep-Cell and named as Chi-56A. Its molecular weight was estimated to be 53kDa monomer and the isoelectric point (pI) was pH 4.3. The pH and temperature for the optimum activity of Chi-56A were pH 6.0 and $65^{\circ}C$, respectively. Chi-56A was stable up to $65^{\circ}C$ and in alkaline region. Its $K_{m}$ value for colloidal chitin was 17.33g/L. HPLC analysis of the reaction products confirmed that Chi-56A was an exo type chitinase.e.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.621-626
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• 2016

The present study evaluated the variations in soil microbial population of controlled horticultural land used for lettuce (Lactuca sativa) cultivation by their fatty acid methyl ester and chemical properties. We utilized four treatment groups, no treatment (NT), culture medium (CM), Bacillus subtilis S37-2 (KACC 91281P) ${\times}10^6CFU\;mL^{-1}$ (BS1), and Bacillus subtilis $S37-2{\times}10^7CFU\;mL^{-1}$ (BS2) and analyzed these variations throughout the before treatment and harvesting stage. The chemical properties such as pH, organic matter, available phosphate, and electrical conductivity in soils before treatment and harvesting stage showed no significant difference among the treatments. Total numbers of bacteria and microbial biomass C in soil treated with BS1 were larger than those of NT, CM, and BS2, whereas total number of fungi at the harvesting stage was significantly lower in the BS1 soil than in the NT and CM soils (P < 0.05). On basis of leaf length, leaf width, leaf number and leaf weight, the growth characteristics lettuce on the soil treated with BS1 and BS2 was faster than those of NT and CM soils. Yield of lettuce with treated BS1 and BS2 were 35% and 29% more than that of NT, respectively.

• Korean Journal of Agricultural Science
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• v.34 no.2
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• pp.161-170
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• 2007

To characterize $\gamma$-glutamyltranspeptidase ($\gamma$-GTP or ggt; EC 2. 3. 2. 2.) gene of Bacillus subtilis BS 62, the $\gamma$-GTP gene of BS 62 was prepared from PCR products amplified with the chromosomal DNA. The $\gamma$-GTP gene of about 2.5 kb was sequenced, and its homology was compared with the other ggt genes which were reported previously. The base sequence of the gene appeared to have an open reading frame of 1,758 bp encoding a protein of 62,175 Da. The coding region was flanked by putative ribosome binding site - AGGAGG of 7th to 12th upstream - and the stem-loof sequence was followed by transcription terminator codon. Homology of the amino acid residues sequence consisting of 587 amino acid residues was found as 98% with Bacillus subtilis gene (BSU49358), 97.4% with that of Bacillus subtilis KX 102, 37% with Pseudomonas sp. A14 (S63255) and 38% with Streptomyces avermitils (AP005028).

• Food Science and Biotechnology
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• v.16 no.2
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• pp.320-324
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• 2007

The bacterial diversity in Korean soybean-fermented foods was investigated using a PCR-based approach. 16S rRNA sequences were amplified and cloned from two different soybean-fermented foods such as doenjang (soybean paste), and ganjang (soybean sauce). Staphylococcus equorum (60.6%), Tetragenococcus halophila (21.2%), Leuconostoc mesenteroides (9.1%), Lactobacillus sakei (6.1%), and Bacillus subtilis (3.0%) were detected among clones isolated from soybean paste samples and Halanaerobium sp. (37.5%), Halanaerobium fermentans (37.5%), T. halophila (12.5%), Staphylococcus sp. (6.3%), S. equorum (3.1%), and B. subtilis (3.1%) were detected among clones isolated from soybean sauce. Our approach revealed different bacterial distributions and diversity from those previously obtained using culture-dependent methods.