PURIFICATION AND PROPERTIES OF AN ENDOGLUCANASE FROM A BACILLUS ISOLATE

The thermophilic soil isolate, Bacillus sp. PDV, produced endoglucanase when grown on glucose and could not utilize carboxymethyl cellulose (CMC) or Avicel as growth substrates. The CMCase was purified on a DEAE-Sephacel ion exchange column followed by Biogel-A-0.5m and Superose-6 gel filtration columns. The purified CMCase was found to be homogeneous on polyacrylamide gel electrophoresis with silver staining and had a molecular weight of 33,000 (SDS-PAGE and Sephadex G-100 gel filtration). It showed activity towards crystalline forms of cellulose such as cotton and Avicel and was stable in the pH range of 4-10 and temperature up to 60°C. The enzyme hydrolysed CMC with pH and temperature optima of 5.0 and 60°C and a Km of 0.588 mg ml-1. The enzyme activity was completely inhibited by Hg2+, while other metalions, chelators, various oxidizing agents, and repeated freezing and thawing had no marked effect on activity. Reducing agents, in general, increased the activity. © 1990.