SBIR Phase I: Evaluation of recombinant HED2 proteins as synergists for cellulosic biofuel production

This Small Business Innovation Research Phase I project will explore the feasibility of recombinant expression and use of a selected group of plant proteins to enhance cellulase performance in the conversion of cellulosic biomass to simple sugars for production of biofuels such as ethanol. Cellulosic biomass is an attractive energy feedstock because supplies are abundant both domestically and globally. Current methods to break down biomass into simple sugars for fermentation into ethanol are inefficient and constitute a significant barrier to producing ethanol at volumes and costs competitive with gasoline. A primary research objective for Phase I is to achieve gram-scale expression of a representative sample of naturally-occurring and artificially-constructed homologs of Expansin Domain-2 (HED2) proteins in a heterologous expression system. The recombinant proteins will be assayed for cellulase synergism using commercial cellulases and biomass samples under conditions that approximate industrial processes. The broader impacts of this research will be to significantly improve the breakdown of cellulosic feedstocks by improving enzyme performance. It is widely recognized that measurable improvements in enzyme performances are required in order to reach an economically viable, biomass-based, fuel production process. While significant strides have been made to reduce production-related enzyme costs, overall cellulase performance must be improved in order to achieve a cost-effective process. An accessory protein, which enhances cellulase activity, would be a key development in unlocking the energy potential of recalcitrant cellulose to potentially reduce the nation's dependence of fossil fuels.