Saccharification of Pre-treated Rice Straw by Recombinant Cellulases

Abstract

This study investigated the saccharification of delignified rice straw using recombinant cellulases to release reducing sugars. Compositional analysis of the native rice straw revealed presence of 35.5% cellulose, 20% hemicellulose, and 22.2% lignin. Acid and alkali pre-treatment were applied to non-grinded, grinded and trash rice straw. Non-grinded biomass had the highest cellulose content of 68%. Delignification and pre-treatment efficiencies were 94.6% and 97.3% respectively for non-grinded biomass. The enzymatic saccharification of pre-treated non-grinded rice straw using recombinant cellulases yielded 79 mg/g total reducing sugar using enzyme ratio of CtCel8A:CtCBH5A:HtBgI (250:20:30 U/g) after 12hrs at 50°C. This study demonstrates the potential of recombinant cellulases for efficient saccharification after delignification of pretreated rice straw as a valuable method for the production of fermentable sugar for sustainable production of bioethanol.