Neutrophilic Bacillus Strain, KSM-522, That Produces an Alkaline Carboxymethyl Cellulase

Abstract

A strain of Bacillus that produced an alkaline carboxymethyl cellulase (CMCase) was isolated from a soil sample and was found to be taxonomically similar to Bacillus pumilus. The growth rate and production of CMCase were greater during cultivation in neutral medium than in alkaline medium. Glucose, sucrose, cellobiose, maltose, starch and xylan, in addition to carboxymethyl cellulose, induced the production of the CMCase.
The CMCase, partially purified by precipitation with ammonium sulfate, was very active over the pH range of 7 to 10 and was fairly stable over a broad pH range (pH 5-12). The reaction catalyzed by the CMCase showed an optimum temperature of about 50°C and the enzyme was stable at temperatures up to 50°C or higher at pH 9. The partially purified enzyme preparation exhibited essentially no activity toward insoluble cellulosic materials such as filter paper, Avicel, cellulose powder, or alkali- or H₃PO₄-swollen celluloses, nor was it active toward cellobiose or p-nitrophenyl-β-D-cellobioside.
The CMCase activity was characteristically stable in the presence of surfactants, chelating agents and proteolytic enzymes used as components of laundry detergents.