Extracellular cellulase system of a thermotolerant streptomycete: Streptomyces albaduncus

During screening for cellulolytic streptomycetes from different natural substrates, Streptomyces albaduncus thermotolerant streptomycete was selected for detailed studies because of its comparatively better yield and ability to grow at higher temperatures (up to 47 degrees C). The production of cellulases of this strain was studied under different growth conditions. It produced optimum levels of all the three constituents of cellulase complex at pH 7.0, and 37 degrees C in the presence of 3% substrate. When grown as submerged culture complex under these conditions, the strain produced considerable amounts of filter paper degrading activity (FPase), carboxymethyl cellulose hydrolyzing activity (CMCase) and beta-glucosidase activity in the extracellular supernatant. It exhibited good overall cellulolytic activity as measured using cotton as substrate. The maximum yields of FPase and CMCase were obtained within 96-120 h and beta-glucosidase after 48 h. The optimum incubation temperature for enzyme activities was 50 degrees C and optimum pH in the range of 6.0-6.5. After analyzing the cellulase complex of S. albaduncus, we are now capable to improve it genetically for superior yields.