Cellulase complex of a mesophilic Streptomyces strain

Various cellulolytic streptomycetes were isolated from natural environments. The cellulase production of one of these mesophilic Streptomyces strains, identified as S. flavogriseus was studied. When grown as a submerged culture with 1% microcrystalline cellulose (Avicel) as substrate, the strain produced considerable amounts of beta-1,4-glucan glucanohydrolase (EC 3.2.1.4; CM cellulase) in the extracellular supernatant and exhibited good overall cellulolytic activity as measured using filter paper (FP cellulase) and cotton as substrates. The maximum enzyme yields were obtained after 72 h of incubation at 30 degrees C. The optimal conditions for the FP cellulase activity were found at pH 5.6 and 40 degrees C. All beta-glucosidase and cellobiase activities were found in the mycelial fraction of the culture and could be obtained in soluble form by sonication.