• The Korean Journal of Food And Nutrition
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• v.1 no.2
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• pp.68-75
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• 1988

A strain of alkalophilic Bacillus sp. YS-309 has been isolated from domestic soil. It belongs to genus Bacillus from its morphological and biochemical characteristics. The strain grows better in the alkaline media rather than in the neutral media. The optimum pH and temperature for growth were observed at 8.5 and 4$0^{\circ}C$, respectively. Glucose, lactose and maltose were appeared as good carbon source but soluble starch and fructose were utilized uneffectively for growth. Concentrations of lactose had affected both the cellular growth and the enzyme productions. The maximum growth and the highest enzyme productions were obtained at 0.5%(w/e) of lactose added in the media. B-Galactosidase from Bacillus sp. YS-309 was produced inducibly into the cell and total enzyme activities per ml were gradually decreased when the concentration of glucose increased.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.208-214
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• 2009

To avoid ambiguity in counting the number of colony, about 1,500 of colonies grown on B. cereus selective agar plates were grouped into 12 types by morphological difference and then identified by biochemical and 16S rDNA nucleotide sequence. Among them, seven colony types with 11 to 15 mm diameters of halo were identified as B. cereus or B. cereus subsp. cytotoxis. Five mm sized colonies with no halo, which have not been considered as B. cereus according to the manufacturer's manual, were identified as B. cereus. A colony type with double halos of only 6 mm in diameter was also B. cereus. Other three types were proven to be Enterococcus sp., Brevibacillus sp., and B. subtilis, respectively. PCR results showed that only 9 types that are identified as B. cereus strains harbor at least one of B. cereus toxin genes.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1241-1255
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• 2021

This study was carried out to explore a non-chemical strategy for enhancing productivity by employing some antagonistic rhizobacteria. One hundred eighteen bacterial isolates were obtained from the rhizospheric zone of various crop fields of Gangwon-do, Korea, and screened for antifungal activity against Fusarium wilt (Fusarium oxysporum f. sp. lactucae) in lettuce crop under in vitro and in vivo conditions. In broth-based dual culture assay, fourteen bacterial isolates showed significant inhibition of mycelial growth of F. oxysporium f. sp. lactucae. All of the antagonistic isolates were further characterized for the antagonistic traits under in vitro conditions. The isolates were identified on the basis of biochemical characteristics and confirmed at their species level by 16S rRNA gene sequencing analysis. Arthrobacter sulfonivorans, Bacillus siamensis, Bacillus amyloliquefaciens, Pseudomonas proteolytica, four Paenibacillus peoriae strains, and Bacillus subtilis were identified from the biochemical characterization and 16S rRNA gene sequencing analysis. The isolates EN21 and EN23 showed significant decrease in disease severity on lettuce compared to infected control and other bacterial treatments under greenhouse conditions. Two bacterial isolates, EN4 and EN21, were evaluated to assess their disease reduction and growth promotion in lettuce in field conditions. The consortium of EN4 and EN21 showed significant enhancement of growth on lettuce by suppressing disease caused by F. oxysporum f. sp. lactucae respectively. This study clearly indicates that the promising isolates, EN4 (P. proteolytica) and EN21 (Bacillus siamensis), can be commercialized and used as biofertilizer and/or biopesticide for sustainable crop production.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.86-91
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• 1996

Thermostable $\beta$-mannanase from Bacillus sp. YA-14 was purified by acetone precipitation, CM-cellulose, Sephadex G-100 and hydroxyapatite column chromatography from culture supernatant. The final enzyme preparation appeared to be homogeneous on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). $\beta$-Mannanase appeared to be a monomeric protein with a molecular weight of 67, 000 daltons. The optimal pH and temperature of the enzyme reaction were pH 6.0 and $75^{\circ}C$ , respectively. The enzyme was stable at a pH range of 6.0 to 9.0 and at temperatures between 45 and $85^{\circ}C$. The kinetic constants of $\beta$-mannanase as determined with a galactomannan (locust bean) as substrate were a Vmax of 25 unit/ml and a Km of 1.1 mg/ml. The enzyme had only limited activity on galactomannan substrate. It was suggested that mg $\beta$-mannanase activity is limited by the number of branched $\alpha$-galactose residues.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.290-293
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• 2001

In this study, media optimization by statistically designed experiments stimulated an increase in cell growth of Bacillus sp. during batch cultivation. Plackett-Surman design method selected 3 components among 7 components of production medium. Box-Behnken design method calculated the optimum concentration of selected components by Plackett-Surman design. In the optimized medium, viable cell number increased 2 times. Addition of antifoam effected the cell growth depending on the type of antifoam Vegetable oil, are a carbon source and an antifoam. increased cell growth and controlled foaming

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.41-48
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• 1994

The xylanase from alkali-tolerant Bacillus sp. YA-14 was purified to homogeneity by CM-cellulose, Sephadex G-50, and hydroxyapatite column chromatographies. The molecular weight of the purified enzyme was estimated to be 20, 000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme slightly hydrolyzed carboxymethyl cellulose and Avicel, but did not hydrolyze soluble starch, dextran, pullulan, and ${\rho}-nitrophenyl-{\beta}$-D-xylopyranoside. The maximum degree of hydrolysis by enzyme for birchwood xylan and oat spelts xylan were 47 and 40%, respectively. The Michaelis constants for birchwood xylan and oat spelts xylan were calculated to be 3.03 mg/ml and 5.0 mg/ml, respectively. The activity of the xylanase was inhibited reversibly by $HgCl_2$, and showed competitive inhibition by N-bromosuccinimide, which probably indicates the involvement of tryptophan residue in the active center of the enzyme. The Xylanase was identified to be xylose-producing endo-type xylanase and did not show the enzymatic activities which cleave the branch point of the xylan structure.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.344-349
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• 2004

A gene encoding inulin-degrading enzyme of Bacillus sp. snu-7 with ORF of 1536 nucleotides was cloned. And it was overexpressed as His-tagged protein in E. coli BL21(DE3) pLysS using pRSET B vector containing mature enzyme sequence. Maximum enzyme production was achieved by IPTG (0.1 mM) induction at $OD_{600}$ 1.2 and $30^{\circ}C$ followed by 6 h incubation. The expressed protein purified through immobilized metal affinity chromatography showed molecular mass of 60 kDa on SDS-PAGE. Results of thin-layer chromatography using inulin as a substrate showed the enzyme to be an exotype inulinase capable of producing only monomeric fructose as a product. $K_m$ and $k_{cat}$, for the hydrolyses of inulin and sucrose were $2.28\pm0.08$ mM and 358.05$\pm$20.38 $min^{-l}$, and 22.02$\pm$0.41 mM and 4619.11$\pm$215.12 $$min^{-1}, respectively. Optimal activity of the exoinulinase occurred at pH 7.0 and $50^{\circ}C$.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.293-298
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• 2005

Lab scale experimental study was carried out for SBR process, to investigate the effects of influent ship sewage organic compound removal and Bacillus sp. state on design parameters. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. The performance load of SBR process was shown to be 0.095kg ${\cdot}$ TOC/$m^{3}$ ${\cdot}$ day. The pH was decreased from 8.1 to 7.0 within 30 min and increased to 7.3 at the end of anoxic stage, and these phenomena were explained. The sluge produced in the SBR process is characterized by low generation rate (about 0.36kg ${\cdot}$ MLSS/kg ${\cdot}$ TOC) and excellent settleability. The number of Bacillus sp. in the SBR was 24.2%, indicating that Bacillus sp. was a predominant species in the reactor.

• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.475-480
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• 2005

Lab scale experimental study was carried out for SBR process, to investigate the effects of influent ship sewage organic compound removal and Bacillus sp. state on design parameters. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than $92.0\%$ of chemical oxygen demand(COD) were removed. In addition, about $84.0\%$ of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged $93\%$. The performance load of SBR process was shown to be $0.095kg{\cdot}TOC/m3{\cdot}day$. The pH was decreased from 8.1 to 7.0 within 30 min and increased to 7.3 at the end of anoxic stage, and these phenomena were explained. The sludge produced in the SBR process is characterized by low generation rate (about $0.36kg{\cdot}MLSS/kg{\cdot}TOC$) and excellent settleability. The number of Bacillus sp. in the SBR was $24.2\%$, indicating that Bacillus sp. was a predominant species in the reactor.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.40-47
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• 2005

In order to develop a multi-microbial biofungicide against several important plant pathogenic fungi, strains were isolated from the phtophthora blight suppressive red-pepper field soil of Gyeongsangbuk-do, Korea. Strains AY1, AY6, AB1, BB2 and F4, which had strong antagonistic ability against Phytophthota capsici and Fusarium oxysporum, were selected for their involvement with strains of biocontrol fungicide. There were no antagonism among the selected strains and were compatible for making the biofungicide. Their antagonistic mechanisms, except for strain BB2, were an antibiosis by the production of antibiotic, while BB2 produced not only an antibiotic but also cellulase as an antagonistic mechanism against blight causing P. capsici. They were identified as Halobacterium sp. AB1, Xenorhadus sp. AY1, Bacillus sp. AY6, Bacillus sp. BB2, Zymomonas sp. F4 by various cultural, biochemical test and $Biolog^{TM}$ System 4.0. The highest levels of antifungal antibiotic could be produced after 48 hrs of incubation under the optimal medium which were 0.1% galactose, 0.1% $NaNO_2$, 5 mM $Na_2{\cdot}HPO_4$ (pH 5.5). The cultured multi-microbial biofungicide showed strong biocontrol activity against bacterial wilt disease and fusarium wilt disease in cucumber and tomato fields.