Rice straw was used as substrate for cellulase production by solid state fermentation with Aspergillus terreus.
Substrate concentration, moisture ratio, inoculum size and initial pH were optimized using response
surface methodology involving Box-Behnken design. The predicted filter paper activity under optimized
parameters was 9.73 U/g and the validated filter paper activity was 10.96 U/g. Hydrolysis of the biomass
pretreated with 0.125% to 1% NaOH for 24 h at room temperature was performed using crude cellulase
preparation. Treatment with 0.5% NaOH at room temperature for 24 h was the most efficient treatment
method for saccharification. Under the optimized conditions, rice straw yielded 676 mg reducing sugars
per gram of substrate at a cellulase loading of 9 FPU g1 substrate. The present study establishes the possibility
of using mild alkali pretreated rice straw for the production of fermentable sugars with 74.19%
efficiency which can be further utilized for the production of ethanol.