Cellulase Enzymes for the Conversion of Biomass to Biofuels and Chemicals

Cellulose is the most abundant renewable fuel resource on Earth, accounting for about half of the organic material in the biosphere, and is the major polysaccharide found in plant biomass. Cellulosic biomass is a favorable feedstock for fuel ethanol production because it is both readily available and less expensive than either corn or sugarcane. A typical biomass feedstock is comprised of approximately 30-45% cellulose, 30-40% hemicelluloses, 15% lignin and 10% of other components. Nevertheless, substantial hurdles must be overcome before a typical cellulosic feedstock can be utilized effectively and economically as a substrate for the fermentative production of ethanol.  With the annual potential of over 1.3 billion dry tons of biomass, the prospective growth of biofuel and biochemicals derived from cellulose is great.

 The hydrolysis of cellulose, aided by a catalyst, produces glucose, an easily fermentable carbohydrate.  A large amount of research is aimed at the conversion of cellulose to ethanol because, as a source of renewable fuel, the process has great economic potential and is environmentally friendly.  Cellulose is insoluble and crystalline, hence it is largely resistant to microbial attack.  In many biomass utilization schemes the raw material is first treated with dilute acid at moderate temperatures to remove lignin and to speed up cellulose hydrolysis.  The pretreated biomass can then be subjected to carefully chosen mixtures for maximum cost effectiveness. 

The National Renewable Energy Laboratory (NREL) leads the DOE’s National Bioenergy Center, with research spanning the full spectrum from fundamental science to demonstration in fully integrated pilot plants. Scientists at NREL have made modifications to several saccharification enzymes in order to improve thermostability, specific activity, inhibition reduction, and most importantly cut costs.

ID Number	Title and Abstract	Primary Lab	Date
Patent 7,449,550	Superactive cellulase formulation using cellobiohydrolase-1 from Penicillium funiculosum Purified cellobiohydrolase I (glycosyl hydrolase family 7 (Cel7A) enzymes from Penicillium funiculosum demonstrate a high level of specific performance in comparison to other Cel7 family member enzymes when formulated with purified EIcd endoglucanase from A. cellulolyticus and tested on pretreated corn stover. This result is true of the purified native enzyme, as well as recombinantly expressed enzyme, for example, that enzyme expressed in a non-native Aspergillus host. In a specific example, the specific performance of the formulation using purified recombinant Cel7A from Penicillium funiculosum expressed in A. awamori is increased by more than 200% when compared to a formulation using purified Cel7A from Trichoderma reesei.	National Renewable Energy Laboratory	11/11/2008 Issued
Patent 8,283,150	Superactive cellulase formulation using cellobiohydrolase-1 from Penicillium funiculosum Purified cellobiohydrolase I (glycosyl hydrolase family 7 (Cel7A)) enzymes from Penicillium funiculosum demonstrate a high level of specific performance in comparison to other Cel7 family member enzymes when formulated with purified EIcd endoglucanase from A. cellulolyticus and tested on pretreated corn stover. This result is true of the purified native enzyme, as well as recombinantly expressed enzyme, for example, that enzyme expressed in a non-native Aspergillus host. In a specific example, the specific performance of the formulation using purified recombinant Cel7A from Penicillium funiculosum expressed in A. awamori is increased by more than 200% when compared to a formulation using purified Cel7A from Trichoderma reesei.	National Renewable Energy Laboratory	10/09/2012 Issued