Production of a Thermostable and Alkaline Chitinase by Bacillus thuringiensis subsp. kurstaki Strain HBK-51

Abstract EN

This paper reports the isolation and identification of chitinase-producing Bacillus from chitin-containing wastes, production of a thermostable and alkaline chitinasese, and enzyme characterization.

Bacillus thuringiensis subsp.

kurstaki HBK-51 was isolated from soil and was identified.

Chitinase was obtained from supernatant of B.

thuringiensis HBK-51 strain and showed its optimum activity at 110°C and at pH 9.0.

Following 3 hours of incubation period, the enzyme showed a high level of activity at 110°C (96% remaining activity) and between pH 9.0 and 12.0 (98% remaining activity).

Considering these characteristics, the enzyme was described as hyperthermophile-thermostable and highly alkaline.

Two bands of the enzyme weighing 50 and 125 kDa were obtained following 12% SDS-PAGE analyses.

Among the metal ions and chemicals used, Ni2+ (32%), K+ (44%), and Cu2+ (56%) increased the enzyme activity while EDTA (7%), SDS (7%), Hg2+ (11%), and ethyl-acetimidate (20%) decreased the activity of the enzyme.

Bacillus thuringiensis subsp.

kurstaki HBK-51 is an important strain which can be used in several biotechnological applications as a chitinase producer.