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

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