Monday, May 2, 2011
Grand Ballroom C-D, 2nd fl (Sheraton Seattle)
Biofuels are of rapidly growing interest for reasons of climate change, sustainability, and energy security and diversity. In the last decade a tremendous focus has been put on utilizing fermentable sugars from lignocellulose, the largest known renewable carbohydrate source, for the production of second generation bioethanol. Hydrolysis of lignocellulose carbohydrates into fermentable sugars requires a number of different cellulases and hemicellulases. Within DSM R&D activities are focused, among others, on improving our advanced, thermophilic fungal host expression system and developing a robust fermentation process for efficient and cost effective cellulolytic enzyme production. The DSM thermophilic enzyme “cocktail” is composed of a number of cellulases and hemicellulases that can effectively hydrolyze lignocellulosic feedstocks such as washed, pretreated wheat straw. Classical strain improvement combined with fermentation optimization resulted in mutants with a 4 to 5-fold improvement in cellulase production and partial released of glucose repression of enzyme production. Proteomic characterization of selected mutants confirmed the increase in several key cellulases, hemicellulases, and several proteins that may function as helper proteins in cellulose hydrolysis.