• Journal of Life Science
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• v.21 no.4
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• pp.589-595
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• 2011

This work focused on screening and characterizing antibiotic-producing actinomycetes to develop new antibiotics that can overcome the growing resistance of disease-causing microbes. One-hundred actinomycetes strains were isolated from soil samples from Chungcheongbuk-do, Korea using various kinds of actinomycetes isolation media, including a starch casein agar medium and potato dextrose agar (PDA). Among them, strain BCNU 1030 was determined to show strong antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA). Biochemical, physiological, and 16S rRNA sequence analyses indicated that strain BCNU 1030 belonged to the genus Streptomyces. Strain BCNU 1030 exhibited antibiotic activity against a wide range of bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration (MIC) of BCNU 1030 dichloromethane extract was determined to be $0.78\;{\mu}g/ml$ for MRSA CCARM 3090. Therefore, Streptomyces sp. BCNU 1030 has potential for anti-MRSA drug development.

• Journal of Life Science
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• v.22 no.9
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• pp.1194-1200
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• 2012

Lactic acid bacteria are generally recognized as beneficial probiotic organisms. Recent studies revealed that the potential of probiotic strains was essentially dependent on the bacterial-binding and adhesion capabilities to gut epithelial cells and the hydrophobicity of the cell surface. In this study, we screened some indigenous lactic acid bacteria from Kimchi and selected one lactic acid bacterium as a potential probiotic based on its cell surface hydrophobicity. Analysis of the 16S rRNA gene sequences of probiotic isolates indicated that the selected isolate (BCNU 9070 strain) was a member of Pediococcus pentosaceus. P. pentosaceus BCNU 9070 showed resistance to bile acids and acidic pH. The P. pentosaceus BCNU 9070 strain also inhibited the cell growth of six food-borne pathogens including Listeria monocytogenes and Shigella sonnei. In addition, the P. pentosaceus BCNU 9070 strain expressed bile salt hydrolase activity and showed an ability to assimilate cholesterol in vitro. On the basis of these results, P. pentosaceus BCNU 9070 is considered to have probiotic potential for applications in functional foodstuffs.

• Journal of Life Science
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• v.29 no.1
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• pp.84-89
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• 2019

Previous screening of novel antibacterial agents revealed that some bacterial isolates exhibited antibiotic activity against both gram-positive and gram-negative bacteria and that they showed antibacterial activity, even against methicillin-resistant Staphylococcus aureus (MRSA). Among these isolates, one bacterial strain, BCNU 1204, was identified as Pseudomonas aeruginosa using phenetic and phylogenetic analysis, based on 16S ribosomal RNA gene sequences. The maximum productivities of antimicrobial substances of BCNU 1204 were obtained after being cultured at $35^{\circ}C$ and pH 7.0 for 4 d in King's medium B (KMB). Dichloromethane (DCM) and ethylacetate (EA) extracts of P. aeruginosa BCNU 1204 exhibited strong antimicrobial activity, particularly against gram-positive bacteria. The EA extracts exhibited broad-spectrum activity against antibiotic resistant strains. Fraction 5-2, was obtained by recycling preparative liquid chromatography (LC) and preparative thin-layer chromatography (TLC) and was identified as phenazine-1-carboxylic acid belonging to phenazines using gas chromatography and mass spectrometry (GC/MS). Its minimum inhibitory concentration (MIC) values were $25{\mu}g/ml$, $50{\mu}g/ml$, ${\geq}25{\mu}g/ml$, and ${\geq}50{\mu}g/ml$ for MRSA CCARM 3089, 3090, 3091, and 3095 strains, respectively. P. aeruginosa BCNU 1204 may be a potential resource for the development of anti-MRSA antibiotics. Additional research is required to identify the active substance from P. aeruginosa BCNU 1204.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.390-392
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• 2003

Organic solvent tolerant bacterium, Pseudomonas savastanoi BCNU 106 could utilize trichloroacetic acid, monochloroacetic acid, trichloroethylene, p-dichlorobenzene as a sole carbon source. But Pseudomonas savastanoi BCNU 106 didn't have tolerance about trichloroacetic acid, monochloroacetic acid, trichloroethylene, p-dichlorobenzene. Strain BCNU 106 could utilize to the extend of 30 mM trichloroacetic acid as a sole carbon source on mineral salt medium.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.382-385
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• 2003

Organic solvent tolerant bacterium, designated as strain BCNU 106 is a gram negative, rod-shaped aerobe and grows on benzene, toluene, ethylbenzene, and xylenes (BTEX) as a sole carbon source. According to 16S rDNA analysis and fatty acid analysis, strain BCNU 106 showed highest similarity to Pseudomonas syringae var. savastanoi (Pseudomonas savastanoi). Strain BCNU 106 was able to utilize toluene, ethylbenzene, both o-, m-, p-xylene , m-cresol and o-cresol. The degradation of o-, m-, p-xylene by strain BCNU 106 is particularly important, since o-xylene is a compound of considerable environmental interest, owing to its recalcitrance; and very few microorganism have been reported to utilize both o-, m-, p-xylene as a sole carbon source.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.386-389
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• 2003

Organic solvent tolerance bacteria, Pseudomonas savastanoi BCNU 106 could utilize a high contentration of benzene, toluene, ethylbenzene, xylene isomers (BTEX) as a sole carbon source. It was founded that strain BCNU 106 transformed o-xylene to 2-methylbenzyl alcohol, 2-methylbenzoic acid through direct oxygenation of methyl residue on GC-MS analysis.

• Journal of Life Science
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• v.25 no.3
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• pp.345-348
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• 2015

An organic solvent stable lipase from solvent-tolerant Pseudomonas sp. BCNU 171 had an optimal pH of 8 and an optimal temperature of 37℃. This crude extracellular lipase from BCNU 171 exhibited increased stability in the presence of various types of solvents at high concentrations (25%, v/v). The lipase stability was found to be highest in the presence of xylene (137%), followed by toluene (131%), octane (130%), and butanol (104%). Overall, BCNU 171 lipase tended to be more stable than immobilized commercial lipase (Novozyme435) in the presence of organic solvents. Furthermore, BCNU 171 lipase maintained about 90% of its enzyme original activity in the presence of NH₄⁺, Na⁺, Ba²⁺, Hg²⁺, Ni²⁺, Cu²⁺, and Ca²⁺ion and significantly increased its enzyme activity in the presence of various emulsifying agents. Thus, the organic solvent stable lipase from Pseudomonas sp. BCNU 171 could be usable as a potential whole cell biocatalyst and for synthetic applications of enzymes for industrial chemical processes in organic solvents without using immobilization.

• KSBB Journal
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• v.25 no.2
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• pp.123-129
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• 2010

An endospore-forming, rod-shaped bacterium was isolated from forest soil samples collected at the Taebaek mountain of Gangwon province, Korea, and taxonomically characterized by physiological, biochemical and phylogenetic methods. Its 16S rRNA sequences showed the maximum similarity of 97% with B. amyloliquefaciens. In addition, the isolate BCNU 2002 was determined to have the ability to produce enzymes such as amylase, protease, gelatinase and catalase. The in vitro antifungal activity of Bacillus sp. BCNU 2002 was also examined against human pathogenic fungi such as Aspergillus niger, Candida albicans, Epidermophyton floccosum, Saccharomyces cerevisiae, Trichophyton mentagrophytes and Trichophyton rubrum. A maximum production level of antifungal substances of Bacillus sp. BCNU 2002 was achieved under aerobic incubation at $28^{\circ}C$ for 7 days in LB broth. BCNU 2002 showed strong antifungal activities against T. mentagrophytes and T. rubrum with the range of percentage inhibition from 56.25 to 63.23%. It was also confirmed that ethylacetate extract of cultured broth showed a strong antifungal activity against A. niger, C. albicans, S. cerevisiae and T. rubrum by agar diffusion method. The peptide fraction also exhibited broad antifungal spectrum against various pathogenic fungi. The minimum inhibitory concentration values for active extracts ranged between 125 ${\mu}g$/mL and 1000 ${\mu}g$/mL.

• Journal of Life Science
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• v.22 no.2
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• pp.251-258
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• 2012

The purpose of this study was to investigate the probiotic properties of lactic acid bacterial strains isolated from animal feces. BCNU 9041 and BCNU 9042 isolates were assigned to Lactobacillus brevis on the basis of their physiological properties and 16S ribosomal DNA sequences analysis. They were confirmed as safe bioresources because of their non-hemolytic activities and non-production of harmful ${\beta}$-glucosidase, ${\beta}$-glucuronidase, tryptophanase, or urease. These isolates were also highly resistant to acid (at pH 2.5) and bile acids (at concentration of 0.3%, 0.6%, and 1% oxgall). In addition, they exhibited good antibacterial activity against food-borne bacteria, especially Bacillus cereus, Listeria monocytogenes, and Shigella sonnei. Furthermore, it was demonstrated that they have the highest levels of hydrophobicity and that they showed bile salt hydrolytic and cholesterol assimilation activity. These results suggest that BCNU 9041 and 9042 have good potential for application in functional foods and health-related products.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.801-806
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• 2003

Pseudomonas sp. BCNU 106 accumulated approximately 4.12 mM trehalose after cultivation of 12 hr probably by the arising action of trehalose-6-phosphate synthase/phosphatase. The cDNA clones of trehalose-6-phosphate synthase/ phosphatase were isolated from Pseudomonas sp. BCNU 106, and named as PsTPS and PsTPP(Pseudomonas sp. BCNU 106 trehalose-6-phosphate synthase/phosphatase). The two mRNA levels of trehalose-6-phosphate synthase/ phosphatase peaked at 12 hr after exposure to toluene, and thereafter were declined slightly These results support an important role of trehalose accumulation by expressions of PsTPS and PsTPP in toluene-tolerance of Pseudomonas sp. BCNU 106.