Characterization of Chitinase Produced by the Alkaliphilic Bacillus mannanilyticus IB-OR17 B1 Strain |
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Authors: | G. E. Aktuganov N. F. Galimzianova E. A. Gilvanova L. Yu. Kuzmina T. F. Boyko V. R. Safina A. I. Melentiev |
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Affiliation: | 1.Ufa Institute of Biology, Ufa Federal Research Center,Russian Academy of Sciences,Ufa,Russia |
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Abstract: | The paper reports on the isolation of an extracellular chitinase produced by the alkaliphilic Bacillus mannanilyticus IB-OR17 B1 strain grown in media containing crab shell and bee chitin at a pH of 8–11. The enzyme was 860-fold purified by ultrafiltration and chitin sorption. The molecular weight of the purified chitinase was shown by denaturing electrophoresis to be 56 kDa. The enzyme showed maximum activity at a pH of 7.5–8.0 and 65°C and was stable within a pH range of 3.5–10.5 and temperature range of 75–85°C. With colloidal chitin as substrate, the kinetic characteristics of the chitinase were determined as follows: KM ~ 1.32 mg/mL and Vmax ~ 5.05 μM min–1. N-acetyl-D-glucosamine and its dimer were the main products of enzymatic chitin cleavage, while the trisaccharide was detected just in minor quantities. The chitinase actively hydrolyzed p-nitrophenyl-GlcNAc2 according to the exo-mechanism of substrate hydrolysis characteristic of chitobiosidases. |
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