Tuesday, April 30, 2013
Exhibit Hall
Many factors contribute to the resistance of deconstruction of biomass to fermentable sugars. Among them are the distribution of lignins and the structure of cellulose. Lignins have long been considered as the key factor for the biomass recalcitrance as they block the access of enzyme to digestible cellulose surfaces. On the cell walls of biomass material, structured cellulose macro/microfibers intertwine with lignins and hemicellulose forming composite lignocellulose, thereby causing polymorph in cellulose structure, i.e. crystalline, paracrystalline or amorphous cellulose structures. It has been demonstrated that removing the lignins usually provides better access for the following up enzymatic digestions. The inherent heterogeneity of biomass material has put challenge on the data analysis and interpretation based on ensemble digestion experiments. In situ measurements by the means of microscopic tools would unmask the obscure ensemble averaging effect. We have recently used Stimulated Raman Scattering (SRS) Microscope to compare the digestion of corn stover cell walls by two naturally existing available enzyme systems: fungal cellulases and cellulosome, a multienzyme with size substantially larger than that of individual fungal cellulases.