• The Korean Journal of Mycology
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• v.15 no.1
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• pp.29-37
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• 1987

Cellulolytic mocrooganisms were isolated from the cellulose-cultural properties. Among them, Aspergillus clavatus with the highest cellulase activity was identified by the morphological characteristics and it's enzyme activities were compared on the various cultural conditions. It was found that the induction of carboxymethylcellulase(CMCase), avicelase and salicinase in CMC liquid media showed the highest enzyme acitivity on five day's cultivation at $30^{\circ}C$ and thereafter their activities were gradually decreased with time. After crude extracellular enzymes precipitated with the 70% saturated ammonium sulfate solution were dialyzed with 20 mM acetate buffer pH 6.0, each crude enzyme was examined. The optimal activities of CMCase and avicelase were both found to be at $50^{\circ}C$ and pH 6.0. Their thermal stability was appeared at the $50^{\circ}C$. CMCase and avicelase had the maxima activities with 1.5% and 2.2% substrate concentration, respectively. The concentration of 5 mM $Mg^{++}$ or $Ca^{++}$ was found to have a maximum cellulase activity and its activity was inhibited with more than 5 mM $Cu^{++}$ and $Zn^{++}$ concentration. Cellulase activity was also inhibited sensitively by the inhibitors such as 2-mercaptoethanol, iodine and sodium azide.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.463-479
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• 2005

The Sr and Pb isotopic ratios and chemical composition were measured for atmospheric bulk deposition samples collected in the Jeonju, Gunsan and Namweon areas over a period of one year. Acidity of deposition ranged pH $4\~7$ with little higher in dry season, and around pH 5.0 in rainy season. The EC and TDS of rainy season was low showing dilution effect, and increased during dry season. Sulfate $(SO_4)\;and\;NO_3$ are atmospheric aerosols largely of anthropogenic origin in winter. Sodium was concentrated in winter deposition, Ca was concentrated in spring to summer deposition. Namweon has lower EC and TDS than those of other, and Jeonju has higher. Namweon was concentrated in $HCO_3$ and Cunsan was concentrated in Cl. Aluminium, Cu, and Zn show good correlation index with TDS, indicating of their origin atmospheric. $^{87}Sr/^{86}Sr$ ratios of bulk deposition ranged from 0.7109 to 0.7128. The isotopic variations are correlated with mixing of isotopic compositions of local soils, road deposit and biogenic aerosol. In order to constrain further the origin of aerosols in rainwater, it will be necessary to collect additional Sr isotopic data for aerosols. Lead isotope ratios for all areas were similar and belonged to Pb isotope ratios of Seoul's aerosols, but little different with Beijing's aerosols. It showing that Pb in the Korea mainly derived from the gasoline combustion, not exclusively from the Beijing.