Biochemical characterization of cellulase enzyme by Bacillus cereus isolated from cellulotic waste

Cellulase enzyme is the enzyme synthesized by some bacterial and fungal species and breaks down the ß-1,4 glycoside bonds of cellulose. Cellulase enzyme has a wide range of uses such as food, paper, textile industry, animal feed and detergent production. In this study, which was designed to add a new cellulase enzyme to the existing cellulase enzymes with such a wide industrial use, cellulotic bacteria isolation, identification, partial purification and characterization of the cellulase enzyme synthesized by the identified bacteria were performed. First of all, cellulase enzyme production capacity of thirty bacterial strains isolated from soil samples containing hazelnut wastes was investigated by qualitative assay and it was determined that the best cellulase producer among these bacteria was isolate DU-1. The enzyme producing isolate was identified by morphological, biochemical and molecular techniques and the bacterium was identified as Bacillus cereus DU-1. As a result of enzyme characterization studies, optimum conditions for enzyme production by B. cereus DU-1 bacteria was determined as tryptone (nitrogen source), pH 7.0, 37oC and 24 hours. However, it was determined that the activity of the enzyme (4.73 U/mL) was optimum at 50oC and pH 6.0. As a result of the enzyme kinetic analysis, the Vmax value of the enzyme was found as 3.18 U/mL and the Km value was found as 0.0019 mM. Finally, the enzyme was partially purified by ammonium sulfate precipitation.The molecular size of the partially purified enzyme was determined as approximately 40 kDa by SDS-PAGE and Zymogram analysis.