Characterization of a cellulolytic enzyme from wood degrading bacteria, <i>Bacillus circulans</i>

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