Characterization of a cellulolytic enzyme from wood degrading bacteria, Bacillus circulans

Abstract

This report describes the purification and characterization of an enzyme that exhibits cellulase activity produced by the wood degrading bacteria, Bacillus circulans. The enzyme was purified by ion-exchange chromatography using CM-Sepharose CL-6B, and shown to exhibit hydrolytic activity on carboxymethylcellulose. The molecular weight of the purified enzyme was determined to be 43 KDa by means of SDS-PAGE. The kinetic parameters, and the effects of pH and temperature on the purified enzyme were determined. The enzyme was 4.37 fold and showed a specific activity of 29.13 μg of glucose produced/min/mg protein. The apparent K_m value for the hydrolysis of carboxymethylcellulose was 1.061 ± 1.17 mg/ml with a V_max of 13.75 ± 1.51 μg of glucose produced/ml/min. The enzyme showed an optimum pH value of 9.0 and the optimum temperature was 50 °C. Alkalophilicity and moderate thermostability of this enzyme are some of its essential characteristics that may make it suitable for industrial and biotechnological applications.

Keywords: Bacillus circulans, cellulase, decayed wood, optimum, bacteria, enzyme