• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1507-1514
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• 2008

Cholesterol oxidase catalyses the conversion of cholesterol to 4-cholesten-3-one. This enzyme has been used for clinical assay of human serum cholesterol and for reduction of cholesterol level in foods and feeds. In order to search the microorganism which has a high extracellular and stable activity of cholesterol oxidase, soil microorganisms were screened. As a result, the one with the highest extracellular cholesterol oxidase activity was obtained and named as the BEN 115. The BEN 115 strain was identified as one of the Nocardia species based on our taxonomic studies. The cholesterol oxidase from this strain was shown to have two bands of extracellular proteins on SDS-PAGE and Western blot. Their molecular masses were estimated to be about 55 and 57 kDa, respectively. In addition, this cholesterol oxidase was considerably stable at the broad range of pH $3.5{\sim}9.5$ and at the temperature of $25{\sim}55^{\circ}C$. The optimum pH and temperature of this cholesterol oxidase were pH 5.5 and $35^{\circ}C$, respectively. The activity of extracellular cholesterol oxidase could be enhanced 1.6 to 2.0 folds by the addition of nonionic detergent such as Triton X-114, Triton X-100, or Tween-80 into the culturing broth. The substrate specificities against campesterol, sitosterol and stigmasterol were measured to be 50%, 50%, and 27%, respectively, compared to the cholesterol. These results suggest that Nocardia sp. BEN 115 may be useful as a microbial source of cholesterol oxidase production.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.57-62
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• 2003

A bacteria strain producing extracellular $\beta$-mannanase was isolated from soil and was identified as Bacillus subtilis by 16S rRNA sequence comparison and biochemical determinations. The optimum pH and temperature for the $\beta$-mannanase activity were 5.0 and 5.5$^{\circ}C$, respectively. The zymogram technique revealed a single protein band exhibiting $\beta$-mannanase activity from the culture supernatant. The molecular mass of the enzyme was estimated at approximately 130 kDa. The addition of 0.5% lactose or 0.5% locust bean gum to the LB medium caused to Increase significantly the $\beta$-mannanase productivity from Bacillus subtilis JS-1. The cells grown on LB medium supplemented with lactose produced maximal enzyme activity at the stationary phase. In contrast to this, the $\beta$-mannanase was induced at the logarithmic phase from the cells grown on LB medium supplemented with locust bean gum. The discrepancy in induction times suggests that $\beta$-mannanase was induced by different induction mechanisms depending on the carbon sources in Bacillus subtilis JS-1 .

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.500-512
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• 2009

This study was carried out to evaluate the effect of temperature on soil microbial biomass, enzyme activities, and PLFA content in the volcanic(VAS) and the non-volcanic ash soil(NVAS). The soils were treated with organic materials such as organic fertilizer pelleted(OFPL), organic fertilizer powdered(OFPD), pig manure compost(PMC), and food waste compost(FWC). Two grams of organic materials were well mixed with 30g of dried volcanic and non-volcanic ash soil(< 2 mm) with 50% of soil moisture content. And the soils were incubated at 10, 20, $30^{\circ}C$ in incubator. Soils were analysed on the incubation times as followed; soil pH, total nitrogen, organic matter(at 75, 150, 270 days), microbial biomass C and PLFA (at 75, 270 days), microbial biomass N and soil enzyme(at 150, 270 days). pH values of soils treated with PMC and FWC had no changes on soil type, and incubation temperature. However, the pH was increased with temperature in the soils treated with OFPL. The changes in NVAS was higher than in VAS. Soil microbial biomass C content were high in the condition of high temperature and organic fertilizers treatment in VAS. But the contents were gradually decreased with incubation period in both NVAS and VAS. Soil microbial biomass N was high in NVAS treated with organic fertilizers and in VBS treated with PMC and FWC. PLFA content was higher in NVBS than in VBS at 75 days but showed high in VBS at 270 days. Urease activity of NVBS treated with OFPL showed $10^{\circ}C$ (75.0)> $20^{\circ}C$ (16.3)>$30^{\circ}C$ ($4.6ug\;NH{_4-}N\;g^{-1}\;2h^{-1}$) at 150 days. It were decreased gradually high temperature and time passes. And it showed high at $10^{\circ}C$ in VBS. Glucosidase activity was higher in NVBS than in VBS. Correlation coefficient of between soil microbial biomass C and microbial activity indicators showed that PLFA was high significantly at $r^2=0.91$ in NVBS and ${\beta}-glucosidase$ was $r^2=0.83$ in VBS. Soil microbial activities showed differences in the relative sensitivities of soil type and soil temperature.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.357-363
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• 2012

Ginseng (Panax ginseng C. A. Meyer) is an economically important crop in Korea. While the consumption of the crop is gradually increasing, the yield is decreasing due to the injury of continuous cultivation or infection of soil-borne fungal pathogens such as Cylindrocarpon destructans, Fusarium solani, Rhizoctonia solani and Sclerotinia nivalis. In order to find promising biocontrol agents, we have isolated 439 soil bacteria from ginseng cultivated soil and tested their antifungal activities against ginseng rot pathogens. Among them, 3 strains were finally selected and tested for the elucidation of their genetic and biochemical properties. They were identified as Bacillus amyloliquefaciens using phylogenetic analysis based on 16S rRNA gene sequences. Moreover, all selected strains showed positive reaction for PCR detection targeting biosynthetic gene sequences of iturin A and surfactin. The results provided promising evidences that the bacterial strains isolated from ginseng cultivated soil can be novel biocontrol agents for ginseng cultivaion.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.265-276
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• 2017

Heavy metals leaching from closed mines have been causing severe environmental problems in nearby soil ecosystems. Mine reclamation in Korea has been recently implemented based on the heavy metal immobilization (a.k.a., stabilization). Since the immobilization temporarily fixes the heavy metals to the soil matrix, the potential risk of heavy metal leaching still exists. Therefore the appropriate monitoring and the related policies are required to safeguard the soils, where all the cultivations occur. The current monitoring methods are based on either heavy metal concentration or simple toxicity test. Those methods, however, are fragmented and hence it is difficult to evaluate the site in an integrated manner. In this study, as the integrated approach, ecological functional state evaluation with a multivariate statistical tool was employed targeting physiochemical soil properties, heavy metal concentrations, microbial enzymatic activity, and arsenic respiratory reductase gene quantity. Total 60 soil samples obtained from three mines (Pungjeong, Jeomdong, Seosung) were analyzed. As a result, the stabilized layer soil and lower layer soil have shown the similar pattern in Pungjeong mine. In contrast, Jeomdong and Seosung mine have shown the similarity between the stabilized layer soil and the cover layer soil, indicating the possible contamination of the cover layer soil.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.173-178
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• 2017

This study was conducted to investigate the effect of pyroligneous acids on urea hydrolysis for the purpose of inhibiting ammonia volatilization during urea fertilizer application. Different types of synthetic urease inhibitors have been searched and developed, but their use is limited due to varying inhibition effects on soil urease, and environmental problems. In this study, the effect of pyroligneous acids, a natural substance, on urea hydrolysis in soil was evaluated by analyzing inhibition of urease activity. Pyroligneous acids inhibited plant urease and microbial urease activity, as well as soil urease with various urease complex. In addition, pyroligneous acids exhibited non-competitive urease inhibition effect through urease kinetics and inhibited urea hydrolysis in the soil. This study showed that pyroligneous acids treatment with urea fertilizer decreases the loss of urea fertilizer, improves the efficiency of nitrogen application on plant and reduces the amount of nitrogen fertilizers applied in soil.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.344-351
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• 1990

An alkalophilic microoganism producing a detergent-resistant alkaline protease was isolated from soil and identified as Baeiltus sp. The alkaline protease has been partially purified by ammonium sulfate fractionation, DEAE-Cellulose, CM-Cellulose and Sephdex G-100 column chromatography. The purified alkaline protease was highly active at pH 12-13 toward casein and stable at pH values from 6 to ll. The optimum temperature for the enzyme reaction was $55^{\circ}C$. The enzyme was completely inactivated by diisopropyl fluorophosphate (DFP) indicating that the enzyme was serine protease, but considerabiy stable in the presence of surface active agents.

• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.501-505
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• 1990

Streptomyces sp. KISl3 isolated from soil was found to produce low molecular weight thiol protease inhibitors. The protease inhibitor production was closely linked to the cell growth and regulated by growth condition. The inhibitor was purified from the culture broth through butanol extraction, silicagel 60 column chromatography, Sephadex LH-20 gel filtration and preparative HPLC. The inhibitor showed specific inhibitory activity to thiol protease such as papain, picin and bromelain. The mode of inhibition against papain to Hammersten casein as a substrate was non-competitive.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.587-592
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• 1989

A strain of alkalophilic Bacillus sp. YS-309 capable of producing large amount of $\beta$-galactosidase has been isolated from soil sample. Intracellular $\beta$-galactosidase was purified 6.9 folds by procedures including ammonium sulfate precipitation, DEAE-cellulose chromatography, gel-filtration, DEAE-Sephadex A-50 chromatography with over-all yield of 17.8%. The molecular weight of native enzyme was 205, 000 by HPLC, and SDS-polyacrylamide gel electrophoresis showed that the enzyme consisted of 4 identical subunits with a molecular weight of 56, 000.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.22-28
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• 2004

A new moderate thermophilic bacterial strain DG-22 which produces thermostable xylanase was isolated from a timber yard soil in Kyungju, Korea. On the basis of morphological, biochemical and phylogenetic studies the new isolate was identified as a Paenibacillus species. Production of xylanase in this strain was strongly induced by adding xylan to the growth medium and repressed by glucose or xylose. No cellulase activity was detected. The temperature and pH for optimum activity were 8$0^{\circ}C$ and 5.0-5.5, respectively. The crude xylanase was stable at $60^{\circ}C$ and retained 60% of initial activity after 2h at $70^{\circ}C$. Zymogram analysis of the culture supernatant showed two xylanase active bands with molecular masses of 22 and 30 kDa.