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Characterization of Chitinase Produced by the Alkaliphilic Bacillus mannanilyticus IB-OR17 B1 Strain

Author:
Aktuganov, G. E., Galimzianova, N. F., Gilvanova, E. A., Kuzmina, L. Yu., Boyko, T. F., Safina, V. R., Melentiev, A. I.
Source:
Applied biochemistry and microbiology 2018 v.54 no.5 pp. 505-511
ISSN:
0003-6838
Subject:
Bacillus (bacteria), bees, chitin, chitinase, crabs, electrophoresis, hydrolysis, molecular weight, pH, sorption, temperature, trisaccharides, ultrafiltration
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.