6-06: Novel strains of Trametes versicolor as biological pretreatment agents for lignocellulosic biomass-to-bioenergy strategies

The costs associated with pretreatment of plant-based biomass for bioenergy applications continues to be prohibitive and negatively impacts the commercial viability of lignocellulosic-based bioenergy processes.  Biological pretreatment is a promising, cost effective alternative to traditional, thermochemical-based strategies.  White-rot fungi, such as Trametes versicolor, are among the most attractive groups of organisms with respect to biological pretreatment of plant material, owing to their inherent ability to enzymatically modify the recalcitrant chemical bonds of lignocellulose.  Previous research showed that a cellobiose dehydrogenase (CDH)-deficient strain of Trametes versicolor (m4D) improved the lignin extractability of canola straw while maintaining the cellulose content desirable for biofuel production.  Expanding upon this research, we have used a modified Agrobacterium-mediated transformation method to develop novel T. versicolor RNAi strains deficient in GH61 (a polysaccharide monooxygenase) and ST3 (a sugar transporter).  The efficacy of these strains as biological pretreatment agents for plant biomass (e.g. Miscanthus straw) destined for bioenergy processes was explored.  The results suggest that T. versicolor strains deficient in GH61 and ST3  are unable to efficiently metabolize the cellulosic component of the biomass during enzymatic processing. The fungal pretreated biomass is therefore expected to require less intensive thermochemical pretreatment during bioenergy production processes.