• Journal of Microbiology and Biotechnology
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• v.5 no.4
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• pp.206-212
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• 1995

A strain BL-29, which produces a extracellular lytic enzyme on E. coli was isolated from the soil. The strain was identified as belonging to the genus Bacillus sp. The lytic enzyme was purified to homogeneity by ion exchange chromatography and gel filtration. Specific activity of the purified enzyme was 28, 850 U/mg protein and yield of the enzyme was 5$%$. The purified enzyme showed a single band on SDS-PAGE and its molecular weight was estimated to be 31, 000 by SDS-polyacrylamide gel electrophoresis and gel filtration column chromatography. The optimum temperature and pH were $55^{\circ}C$ and pH 10.0, respectively. The enzyme was stable at $45^{\circ}C$ but enzyme activity was reduced by up to 50$%$ when the temperature was raised to $55^{\circ}C$ for 15 min. Stable range of pH was from 5.0 to 11.0. but Enzyme activity was inhibited by lead-acetate, mercuric chloride, ethylene glycol-bis-[$\beta$-aminoethyl ether]-N, N, $N^1, $N^1$-tetraacetic acid (EGTA), and ethylenediamine tetraacetic acid (EDTA), but not affected considerably by treatment with other chemical reagents.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.820-825
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• 1999

A bacterial strain WN9, which produced a new type of extracellular polysaccharide, was isolated from soil samples. By morphological, physiological, biochemical, and phylogenetic studies, strain WN9 was identified as a Paenibacillus sp. and it was named as Paenibacillus sp. WN9, which produced a high molecular extracellular polysaccharide from glucose. The molecular weight of the exopolysaccharide (EPS-WN9) was estimated to be about 31.5 mega-Da. The FT-IR spectrum of EPS-WN9 revealed typical characteristics of polysaccharides. EPS- WN9 consisted of D-glucose and D-mannose with a molar ratio of 1:1.4 being identified as a neutral sugar component. The acidic component of EPS- WN9 was tyrosine. Rheological analysis of EPS- WN9 revealed that the pseudoplastic property and its apparent viscosity remained stable at various temperatures and pHs.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.56-61
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• 1997

A strain producing immunosuppressive substances was isolated from a soil in Cheju island. By morphological, cultural, and physiological studies, the strain was identified as Streptomyces lydicus MCY-524. Cultured broth was purified by silica gel, sephadex LH-20 and preparative HPLC and gave two immunosuppressive compounds, MCH-22 and MCH-32. They dramatically suppressed the B cell activation with lipopolysaccharide, T cell activation by mixed lymphocyte response, and primary T-dependent antibody response at a final concentration of 1 ${\mu}g$/ml. They also markedly suppressed the proliferation of lymphocytes induced by lipopolysaccharide, pokeweed mitogen, and concanavaline A at the same concentration. Their suppressive activities, which were comparable to those of cyclosporin A, suggested that they were potent and broad immunotoxic agents on the immune functions of murine lymphocytes.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.82-86
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• 1996

Three thousand microbial strains collected from different sources were screened for herbicidal activity. A strain of ME-9189 showed herbicidal activity against Digitaria sanguinalis and Portulaca oleracea was isolated from a mountainy soil. Based on taxonomic studies, the strain was identified as Streptomyces tubercidicus. The active compound of ME-9189 was purified from the culture broth by charcoal, silica gel, sephadex LH-20 column chromatography and crystalization, consecutively. The ME-9189 compound was identified as tubercidin by spectroscopic methods of UV, $^{1}H$ and $^{13}C$-NMR, and EIMS. In the bioassay, growth of radish shoot and root was inhibited by 50% with tubercidin treatment of 10 ppm, showing 2 times higher activity than that of herbicidin A and similar to that of toyocamycin.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.223-232
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• 1985

To find microorganisms of producing $\alpha$-amylase inhibitors, actinomycetes were isolated from soil samples that were collected at different locations in Korea and screened for enzyme inhibitory activity. A strain of these microbes had a high inhibitory activity and was identified as one of the genus Streptomyces by morphological, biochemical and physiological studies according to the methods of the International Streptomyces Project (ISP). The medium used consisted of 3 ％ corn starch, 0.2％ yeast extract and 0.8％ peptone (pH 7.0). When this strain was aerobically cultured in the medium on a rotary shaker, the highest inhibitory activity was obtained after four days. This inhibitor had inhibitory activities on various $\alpha$-amylases and glucoamylase, but not on $\beta$-amylase.

• Korean Journal of Microbiology
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• v.19 no.4
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• pp.163-173
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• 1981

The distribution of methanol-assimilating yeasts on three different sources (elm bark, soil and fresh-water mud) and the growth conditions of a new strain of Candidaboidinii (SIO) wereexamines. From 150 samples, 91 methanol yeasts were isolated through enrichment culture ; they were identified as 77 strains of Candida boidinii including four new strains, 5 isolates of Torulopsis pinus, 3 strains of Hansenula polymorpha and one sstrain of Pichia pastoris respectively. The comparison of these yeasts with three sources indicated that decaying bark of elm tree other two, and that Gandida boidinii was most frequently distributed in all three sources. Four new strains of Candida boidinii were freshly isolated and their taxonomical properties were discussed. Of them, SIO strain was selected and characterized for its growth on methanol. This yeast could grow well on less than 1%(v/v) methanol. However, its growth was inhibited at 10% methanol. The cell yield was 3.1g (dry weight) per 1000ml of mineral mediurr, containing 1%(v/v) methanol as well as 01.% yeast extract as additive. The concentration of 0.1% yeast extract appears to be effective for the biomass production. Optimum conditions for growth on methanol was found to be : $28^{\circ}C,\;NH_4^+$ as nitrogen sources, thiamine as vitamin, and pH 4.5 to 6.0. The cell composition was as follows : crude protein and nucleic acids were 54% and 7% respectively. The amino acids were also described.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.673-679
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• 2004

A microbial cryoprotectant formulation using a W/O/W multiple emulsion system was developed. The psychrotolerant microorganism, B4, isolated from soil in South Korea, was observed by the drop freezing method, in which the microorganism sample inhibited ice nucleation activity. The antifreeze activity was eliminated when the microorganism sample was treated with protease, indicating that the antifreeze activity was due to the presence of antifreeze protein. The result of the l6S rDNA sequencing indicated the B4 strain was most closely related to a species of the genus Bacillus. Culture broth of B4 strain (Bacillus sp.) and rapeseed oil containing 1 % polyglycerine polyricinolate (PGPR) were used as core and wall material, respectively. The most stable W/O emulsion was prepared at a core/oil ratio of 1:2. The highest W/O/W emulsion stability was achieved when the primary emulsion to external aqueous phase containing 0.5% caster oil polyoxyethylene ether $(COG25^{TM})$ ratio was 1:1. Microcrystalline cellulose showed better W/O/W emulsion stability than other polymer types. The viability of cells in a W/O/W emulsion was higher than free cells during storage at $37^\circ{C}$. An acidic pH and UV exposure decreased the viability of free cells, but cells in W/O/W emulsion were more stable under these conditions.

• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.118-123
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• 1999

A bacterial strain, designated T116, degrading terephthalic acid (TPA) was isolated from the soil around Taegu industrial area into which dye works wastewater flow. The isolate was identified as pseudomonas sp. based on its morphological and physiological characteristics. Degradation of TPA by the strain T116 was confirmed with UV scanning and HPLC. About 90% and 98% of TPA were degraded after 36 and 60 hours, respectively, during the culture in a liquid medium containing 0.1% TPA. Addition of KH2PO4 at a final concentration of 100ppm enhanced the chemical oxygen demand (COD) removal rate about 50% from dye works wastewater by Pseudomonas sp. T116. Optimum pH and temperature for COD reduction from wastewater were 7.0 and 3$0^{\circ}C$, respectively. The bacterium was applied to the continuous culture for the treatment of dye works wastewater whose TPA concentration and CODMn were 2,200ppm and 1,620ppm, respectively. It was observed that 90-95% of COD was eliminated after 4 days culture in the continuous culture with a retention time of 37 or 47 hours.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.197-200
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• 1973

A bacterium strain, K-73-3, which was isolated from waste soil Korea brewing factory, could grow on acetate as the sole carbone source and accumulated a considerable amount of L-glutamic acid in the liquid culture medium (20 g/l). This strain was named Corynebacterium sp. by the standard method of taxonomy procedures given in the Manual Microbiological Methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.470-474
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• 2008

The rate-dependent constitutive model and the rate-independent model were analyzed for comparing with the piezocone penetration test and dissipation test. The mathematical expressions of the rate-dependent constitutive model were introduced, and the predictions using the both models were compared with the experimental results of in-situ field test. The rate-dependent model analysis gave better results than the rate-independent model analysis, that is appreciated since the process of the piezocone penetration and dissipation depends on the strain rate. Therefore, it is recommended the concept of the rate-dependent model for the prediction of soil behaviors using the field penetration test.