• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.123-124
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• 2008

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.35-40
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• 1999

Alternan known as a kind of dextran is a linear and cyclic polysaccharide which is synthesized with sucrose by alternaansucrase (EC2.4.1.140) of Leuconostoc mesenteroides. But this polysaccharide is different from dextran in its structure and other properties. For the purpose of applying alternan for the food, cosmetic, and pharmaceutical industries, we isolated an excellent alternan-porducing strain, Leu. mesenteroides CBI-110. The optimum culture conditions were studied to improve the yield, and the activity of alternansucrase was increased up to 33U/ml in the optimum culture media. The concentrations of $Mn^{2+}$ and $Cu^{2+}$ ions were 0.01% and 0.03%, respectively, for the effective production of alternan. Finally, we obtained 25.6g/L of alternan.

• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1572-1577
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• 2008

A facultative dissimilatory metal-reducing bacterium, Shewanella sp. strain HN-41, was used to produce magnetite nanoparticles from a precursor, poorly crystalline iron-oxyhydroxide akaganeite ($\beta$-FeOOH), by reducing Fe(III). The diameter of the biogenic magnetite nanoparticles ranged from 26 nm to 38 nm, characterized by dynamic light scattering spectrophotometry. The magnetite nanoparticles consisted of mostly uniformly shaped spheres, which were identified by electron microscopy. The magnetometry revealed the superparamagnetic property of the magnetic nanoparticles. The atomic structure of the biogenic magnetite, which was determined by extended X-ray absorption fine structure spectroscopic analysis, showed similar atomic structural parameters, such as atomic distances and coordinations, to typical magnetite mineral.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.91-97
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• 1995

The 543 microbial strains were isolated from the rhizosphere in ginseng root rot-suppressive soil. From these, isolate KGM-100 was finally selected for the screening of powerful antagonistic bacterium for the soil-born Fusarium solani causing root rot of many important crops. The isolate KGM-100 was identified as Pseudomonas aeruginosa. Antibiotics produced by the P. aeruginosa KGM-100 were partially characterized as heat-stable and low-molecular weight antibiotics. The strain also produced siderophore, which was assumed to be pseudobactin. Pot test showed approximately 30-50% biological control effects when Fusarium solani-infected soil was treated with the P. aeruginosa KGM-100.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1120-1123
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• 2001

Screening tests against six plant pathogenic fungi were performed in order to develop biopesticides. Actinomycetes were used to discriminate Bacillus thuringiensis for wide use as a microbial pesticide. From more than 100 actinomycetes tested, twelve strains showed potent antifungal activities. We report in vivo screening results from fermentation broths of these twelve strains and identification of the strain taxa.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.1022-1025
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• 2002

Club root is one of the major diseases that occur in crucifers. It is caused by Plasmodiophora brassicae. In order to discover microbial biopesticides against P. brassicae, forty-eight Streptomyces isolated from soil were screened. Among these, three strains showed excellent pesticidal activities. We report results on in vivo screening with fermentation broths of these strains and identification of the strain taxa.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.208-214
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• 2000

A bacterial strain producing extracellular chitosanase was isolated from crab shells and identified as a member of the genus Aureobacterium The production of chitosanase was proportionally related to the microbial growth, induced by the presence of chitosan, and repressed by glucose at 0.5% (w/v) concentration or higher. The optimal culture conditions for the production of chitosase were 3$0^{\circ}C$ and pH 7.0. Among the nitrogen sources tested, incubation with 0.25% (w/v) concentrations of tryptone and casitione showed the best production of chitosanase. The chitosanase of Aureobacterium sp. YL produced chitobiose as a major product and glucosamine, chitotriose, chitotetraose, and chitopentaose as minor products from chitosan.

• Journal of Microbiology and Biotechnology
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• v.20 no.9
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• pp.1295-1299
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• 2010

Recently, recombinant Streptomyces venezuelae has been established as a heterologous host for microbial production of flavanones and stilbenes, a class of plant-specific polyketides. In the present work, we expanded the applicability of the S. venezuelae system to the production of more diverse plant polyketides including flavones and flavonols. A plasmid with the synthetic codon-optimized flavone synthase I gene from Petroselium crispum was introduced to S. venezuelae DHS2001 bearing a deletion of the native pikromycin polyketide synthase gene, and the resulting strain generated flavones from exogenously fed flavanones. In addition, a recombinant S. venezuelae mutant expressing a codon-optimized flavanone $3{\beta}$-hydroxylase gene from Citrus siensis and a flavonol synthase gene from Citrus unshius also successfully produced flavonols.

• Journal of Yeungnam Medical Science
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• v.19 no.1
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• pp.1-10
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• 2002

With the establishment of rapid sequence analysis of 16S rRNA and the recognition of its potential to determine the phylogenetic position of any prokaryotic organism, the role of 16S rRNA similarities in the present species definition in bacteriology need to be clarified. Comparative studies clearly reveal the limitations of the sequence analysis of this conserved gene and gene product in the determination of relationship at the pathogenic strain level for which DNA-DNA reassociation experiments still constitute the superior method. Since today the primary structure of 16S rRNA is easier to determine than hybridization between DNA strands, the strength of the sequence analysis is to recognize the level at which DNA pairing studies need to be performed, which certainly applies to similarities of 97% and higher.

• Microbiology and Biotechnology Letters
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• v.21 no.5
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• pp.486-493
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• 1993

A gram(+) bacteria that produced microbial flocculant was isolated from soil and classified as a Bacillus species and named as Bacillus sp. A56. The culture conditions of the strain for fluocculant production were studied in a shake flask. Optimum temperature and initial pH for flcculant production were 30C and 6.5, respectively. The optimized medium has gollowing composition: glucose 20g/l, NH4NO3 0.5g/l, K2HPO4 1.0g/l, KH2PO4 0.8g/l, MgSO4.7H2O 0.2g/l, MnSO4.4-6H2O 0.3g/l, CaCO3 0.5g/l, yeast extract 0.3g/l, tryptone 0.3g/l in tap water.