Monday, April 30, 2012
Napoleon Ballroom C-D, 3rd fl (Sheraton New Orleans)
The activity of β-glucosidase is one of the limited steps in the saccharification process of lignocellulosic residues since it prevents inhibition of the endoglucanases and exoglucanases caused by the accumulation of cellobiose. The gene bgl A that encodes for a β-glucosidase of C. flavigena PN-120, a derepressed and deregulated double mutant, suffered the insertion of two aspartic, near the hypothetical binding site to carbohydrate as a result of mutagenesis. This change improves the activity and substrate affinity of the respective enzyme compared to the wild enzyme. In this work we express the β-glucosidase of C. flavigena PN-120 in Saccharomyces cerevisiae in order to perform a simultaneous saccharification and fermentation system (SSF). The recombinant yeast obtained by genetic engineering is capable to growth on cellobiose as only carbon source and export extracellularly the mutant β-glucosidase. This yeast has the potential to produce low-cost ethanol using hydrolysates of sugarcane bagasse.