• The Korean Journal of Mycology
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• v.11 no.1
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• pp.15-21
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• 1983

Exodextranase from Aspergillus ustus was purified by chromatography and characterized by various conditions. The optimal pH of the purified dextranase was 6.5 and this enzyme was maximally activated at $40^{\circ}C$. The enzyme was stable at the temperature below $50^{\circ}C$. The enzyme was markedly inactivated by $Hg^{2+},\;Cu^{2+},\;KCN\;and\;Co^{2+},\;but\;Ba^{2+},\;Fe^{2+},$ cysteine, EDTA, and ascorbic acid enhanced the activity of the enzyme. The main products from the hydrolysis of dextran incubated with the dextranase were glucose, isomaltotriose and oligosaccharide. When dextran was incubated with the mixture of pullulanase and ${\alpha}-amylase$, it was hydrolyzed into glucose, isomaltose and oligosaccharide. Polysaccharides in the decade teeth powder were hydrolyzed by the dextranase into glucose, isomaltotriose and oligosaccharides. In the hydrolysis of the teeth powder with the mixture of dextranase, pullulanase and ${\alpha}-amylase$, were proved to be similar to the dextran hydrolysates.

• Korean Journal of Microbiology
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• v.25 no.4
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• pp.346-352
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• 1987

One hundred and seventeen colonies were screened for the detection of the production of exodextranase on the dextran-mineral salts medium. Ten colonies out of them produced the dextranase. Flavobacterium multivorum greatly producing the enzyme was isolated from soil, identified and then studied for various biochemical characteristics. The activity of the dextranase in the cultured medium was high between pH8 and 9 at $35^{\circ}C$, and between $45^{\circ}C$ and $55^{\circ}C$ at pH8. By the growth curves the generation times of the bacterium were approximately 52 minutes in the LB broth, 38 minutes in the LB plus 1% dextran and 660 minutes in the dextran-salts. The strain did not have ant plasmid, and was susceptible to genramicin, cotrimoxazole and cefoperazone, and moderately susceptible to chloramphenicol, cefamandole and cefotaxime, but resistant to ampicillin, cephalothin, tetracycline, amikacin and tobramycin.

• The Korean Journal of Mycology
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• v.11 no.1
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• pp.23-26
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• 1983

Aspergillus ustus was cultured in the salts media contained dextran (2%). Then the cultured liquid media were filtrated and concentrated up to 10 folds by evaporation, and then purified by means of acetone precipitation, of a repeated chromatography on the columns of DEAE-Ccellulose, Biogel P-150, and Sephadex G-200. Total proteins in the initial culture filtrate were 38,500mg, but the final amounts of proteins were 172mg. The specific activity of the protein in the culture filtrate was $1,340\;{\mu}moles$ products per minute per mg protein, but the final specific activity of the protein was $2,448\;{\mu}\;moles$ products per minute per mg protein. The final yields remained about 30% of the initial.