Cellulases of an alkalophilic Bacillus strain isolated from soil

Abstract

A cellulolytic alkalophile, Bacillus sp. No. N-4, was isolated from soil and found to be similar to Bacillus pasteurii, except for its ability to grow at high pH. The isolate grew well at a pH ranging from about 8 to 11 and was a good producer of carboxymethyl cellulase (CMCase) activity, which was associated with a multienzyme system. The crude enzyme preparation strongly hydrolyzed carboxymethyl cellulose and had a broad pH activity curve (pH 5–10). Two alkaline CMCases (enzyme E1 and E2) having an optimal pH for enzyme action at pH 10.0 were partially purified. The enzyme E2 was stable up to 80 °C, and E1 up to 60 °C. Both enzymes hydrolyzed cellotetraose and preferentially yielded cellobiose.