ABSTRACT
A solid state fermentation [SSF] in a laboratory scale was used for cellulase production by T richoderma reesei NRRL 6156 using wheat straw and wheat bran [3:1 w:w] as substrate. The solid substrates [initial water content 54.5 %], supplemented with a SSF mineral medium before optimization showed carboxymethyl cellulase [CMC-ase] and filter paper-cellulase [FP-ase] activities of 129 and 8.8 U/g respectively. After a three-step medium optimization CMC-ase activity had significantly increased to ca. 2690 U/g culture, while FP-ase increased to 16 U/g culture. The optimized SSF medium allowed 17.5 and 1.2 fold respective increases in CMC-ase and FP-ase activities. The maximum extracellular cellulase production was obtained after 10 days. Adding 20g/l 0f [NH4]2S04 led to a proportional increase in cellulase activity. Combined supplementation with [NH4]2S04, urea wheat bran and wheat straw have a stimulating effect on cellulase production. Furthermore, the concentration of KH2P04 showed a strong effect on enzyme production, suggesting the importance of buffering of the SSF medium