• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.384-390
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• 2009

An antifungal antibiotic-producing bacterium was isolated from soil and identified as Bacillus sp. CJ-1. The culture supernatant was found to have a strong and stable antifungal activity against Colletotrichum gloeosporioides. Culture conditions for the maximum antifungal activity were examined. Glucose and yeast extract were selected as the best carbon and nitrogen sources. The optimum C/N ratio was 3. The optimum temperature and initial pH were determined as $35^{\circ}C$ and 6.0, respectively. Under these conditions, the production for the antibiotic was maximized at 72 hr at $35^{\circ}C$ after cultivation. Microscopic observation showed that the culture supernatant of Bacillus sp. CJ-1 had a strong inhibitory activity on the mycelial growth of the test strain at above $12.5\;{\mu}L\;mL^{-1}$ of concentration.

• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.141-145
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• 1998

Overproduction of intracellular ${\beta}$-glucosidase was attempted by modifying the promoter region of a ${\beta}$-glucosidase gene cloned from Cellulomonas fimi and expressing it in Bacillus subtilis DB 104. A strong engineered promoter, BJ27UΔ88, was fused to the ${\beta}$-glucosidase gene after removing its native promoter. An effective Shine-Dalgamo sequence (genel0 of phage T7) was inserted between the promoter and the ${\beta}$-glucosidase structural gene. The modified gene was overexpressed in B. subtilis and produced 1121.5 units of ${\beta}$-glucosidase per mg protein which is about $12\%$ of total intracellular protein. Secretion of overproduced intracellular ${\beta}$-glucosidase was attempted by using the signal sequence of the Bacillus endoglucanase gene as well as an in-frame hybrid protein of endoglucanase. The hybrid protein was normally secreted into the culture medium and still retained ${\beta}$-glucosidase activity.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.65-72
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• 1994

Purification and characterization of pectate lyase from Bacillus sp HSA-925. Bacillus sp. HSA-925 isolated from soil produced constitutively an extracellular pectate lyase when cultivated in LB broth. The pectate lyase(EC 4.2.2.2) was purified from the cuylture broth by preciptation with ammonium sulfate, followed by column chromatography on CM-cellulose C-50 and repeated gel filtration on Sephadex G-75G. The enzyme had a molecular weight of 32-33 kDa. The activity was mazimum at pH 9.5 AND 45$\CIRC $C. The enzume activity was stable at 55$\circ $C for 15 min and between pH7-12. The activation energy, Km and V$_{max}$ for the pectate lyase were 5.8779 kcal/mol, 6.33$\times $10$^{-2}$ mol/ml and 2.09$\times $10$^{2}$ $\mu $mol/min respectively. The enzyme was activated by Ca$^{2+}$, Cu$^{2+}$ and inhibited by Li$^{+}$, Hg$^{2+}$, EDTA.

• Microbiology and Biotechnology Letters
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• v.21 no.5
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• pp.446-452
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• 1993

The cholesterol oxidase produced from Bacillus sphaericus was purified and characterized. Through a series of purification procedures including DEAE-Toyoperal 650C, Sephadex G-200 and DEAE-Sephadex A-50 column chromatography, the purified enzyme was shown to have a specific activity of 0.179 units/mg protein having 31.8 fold purification and final yield of 12%. The molecular weight of the enzyme was estimated to be 47kDa and 47.tkDa by Sephadex G-200 chromatography and SDS-PAGE. The optimum temperature and pH for the enzyme were 30C and 6.0, respectively. The activity of the purified cholesterol oxidase was inhibited by Fe2+ and Hg+.

• The Korean Journal of Food And Nutrition
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• v.5 no.2
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• pp.77-83
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• 1992

The optimum conditions and mechanisms for the plasmid-mediated genetic transformation of intact cells of Bacillus brevis Pl76-2, an extracellular protein producing bacterium by electroporation were investigated. It was found that pUB110 Plasmid DNA can be introduced into intact bacterial cells by electroporation. The frequency of transformation by this electroporation system depended upon the initial electric field strength, the capacity of the electric discharge capacitor, growth stage, number of successive pulses and composition of electroporation buffer. It was effective for transformation that cells were harvested, washed and resuspended with HSM [7M HEPES(PH 7.4), 272mM sucrose, 1 mM MgCl2] electroporation buffer when cell growth was attained to 1.2 at OD660. A maximum frequency of transformation of 2.40$\times$104 transformants per$\mu$g plasmid DNA was obtained by two succesive Pulses with an initial electric field strength of 12.5kV/cm and with a capacitance of 7.3uF.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.152-164
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• 2015

Biological control of major rice diseases has been attempted in several rice-growing countries in Asia during the last few decades and its application using antagonistic bacteria has proved to be somewhat successful for controlling various fungal diseases in field trials. Two novel endophytic Bacillus species, designated strains YC7007 and $YC7010^T$, with antimicrobial, plant growth-promoting, and systemic resistance-inducing activities were isolated from the roots of rice in paddy fields at Jinju, Korea, and their multifunctional activities were analyzed. Strain YC7007 inhibited mycelial growth of major rice fungal pathogens strongly in vitro. Bacterial blight and panicle blight caused by Xanthomonas oryzae pv. oryzae (KACC 10208) and Burkholderia glumae (KACC 44022), respectively, were also suppressed effectively by drenching a bacterial suspension ($10^7cfu/ml$) of strain YC7007 on the rhizosphere of rice. Additionally, strain YC7007 promoted the growth of rice seedlings with higher germination rates and more tillers than the untreated control. The taxonomic position of the strains was also investigated. Phylogenetic analyses based on 16S rRNA gene sequences indicated that both strains belong to the genus Bacillus, with high similarity to the closely related strains, Bacillus siamensis KACC $15859^T$ (99.67%), Bacillus methylotrophicus KACC $13105^T$ (99.65%), Bacillus amyloliquefaciens subsp. plantarum KACC $17177^T$ (99.60%), and Bacillus tequilensis KACC $15944^T$ (99.45%). The DNA-DNA relatedness value between strain $YC7010^T$ and the most closely related strain, B. siamensis KACC $15859^T$ was $50.4{\pm}3.5%$, but it was $91.5{\pm}11.0%$ between two strains YC7007 and $YC7010^T$, indicating the same species. The major fatty acids of two strains were anteiso-$C_{15:0}$ and iso $C_{15:0}$. Both strains contained MK-7 as a major respiratory quinone system. The G+C contents of the genomic DNA of two strains were 50.5 mol% and 51.2 mol%, respectively. Based on these polyphasic studies, the two strains YC7007 and $YC7010^T$ represent novel species of the genus Bacillus, for which the name Bacillus oryzicola sp. nov. is proposed. The type strain is $YC7010^T$ (= KACC $18228^T$). Taken together, our findings suggest that novel endophytic Bacillus strains can be used for the biological control of rice diseases.

• 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.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.57-62
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• 2001

Twelve antagonistic strains against Fusarium wilt of watermelon-rootstock gourd were selected from 54 bacterial isolates which were isolated from the rhizosphere of crop plants growing in various locations. They showed strong inhibitory effects on growth of Fusarium osysporum f. sp. niveum, the causal agent of watermelon-rootstock gourd Fusarium wilt. Among these antagonists, the isolate YJ-3 was the most pronounced in growth-promoting ability for watermelon-rootstock gourd. The growth of watermelon-rootstock gourd in bed soil inoculated with YJ-3 was better by 46 and 13% than those in commercial bed soil alone and in bed soil inoculated with commercial microbial inoculant, respectively. The antagonistic plant growth-promoting rhizobacterium, strain No. YJ-3, was identified as Bacillus sp. on MIDI system. Furthermore, Bacillus sp. YJ-3 showed antifungal activity on growth against Alternaria cucumerina, Botrytis cinerea, Colletotrichum orbiculare, Didymella bryoniae, Rhizoctonia solani and Fusarium oxysporum.

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.79-83
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• 2011

Over-application of nitrogen fertilizer keeps increasing the salinity in the soils of greenhouse in domestic agriculture. In order to remove the excess amounts of soil nitrate, soil microorganisms which have high capacity of nitrate uptake were isolated from the upland soils and their nitrate uptake activities were measured. Strain GS2 was able to remove 50 mM nitrate within 12 h. After sequence comparison analysis of 16S rRNA gene, the strain was identified and named as Bacillus sp. GS2. When the growth and nitrate uptake activities were measured, maximal values were obtained at $30-40^{\circ}C$ and $37^{\circ}C$, respectively; however, both were optimal at pH 6-8. In the media containing 50 mM nitrate, Bacillus sp. GS2 removed 43 mM nitrate which is corresponding to 86% removal. Similar amounts of nitrate removal were observed at the nitrate concentrations up to 300 mM, showing a saturation in nitrate uptake at concentrations above 50 mM. These results imply that Bacillus sp. GS2 can be a good candidate for the microbial remediation of accumulated environmental nitrate because of its excellent growth and nitrate uptake activity.

• Food Science and Preservation
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• v.14 no.2
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• pp.207-212
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• 2007

The antimicrobial activity of Curcuma aromatica Salab. was investigated. The Curcuma aromatica Salab. extract showed antimicrobial activity against six pathogens tested. These were Listeria monocytogenes ATCC 19115, Pseudomonas fluorescens ATCC 21541,Staphylococcus aureus ATCC 29273, Salmonella typhimurium ATCC 21541, vibrio parahaemolyticus ATCC 17802, and Aeromonas hydrophila KCTC 2358. Antimicrobial activity was alsonoted when the extract was tested against four isolates of Bacillus sp. purified from spoiled tofu. The growth of various pathogens was significantly inhibited (100 10,000-fold) upon growth in tryptic soy broth containing 0.05 0.2%(w/v) Curcuma aromatica Salab. extract(CE), after incubation for 12hr at $37^{\circ}C$. The growth of the four Bacillus isolates was also significantly inhibited in nutrient broth containing 0.05 0.2% CE after incubation for 24hr at $37^{\circ}C$. Although the antimicrobial activity of CE was decreased by heat treatment at temperatures above $80^{\circ}C$, the activity remained relatively high after heat treatment at $121^{\circ}C$ for 15min. The minimum inhibitory concentrations of CE were 0.1 0.3%(v/v culture) for the six pathogens, and 0.2 0.25% for the Bacillus isolates, respectively.