A Rapid, Scalable Method for Plant-Made Production of Cellulases

University Of California-Davis, Davis CA

Investigators

Abstract

This NSF award by the Biotechnology, Biochemical and Biomass Engineering program supports the development of technologies and processes for efficient, rapid and scalable production of cellulase enzymes in plant tissues. To meet the requirements of the Energy Independence and Security Act of 2007, conversion of cellulosic biomass into advanced biofuels will require a significant amount of cellulose degrading enzymes at a low cost. Current methods for production of cellulose and hemicellulose degrading enzymes rely primarily on submerged fungal fermentation and are expensive, energy intensive, generate carbon dioxide, and consume cellulosic feedstock for growth of the production microorganisms. In this project, multiple thermostable cell wall degrading enzymes will be produced in Nicotiana benthamiana (a relative of tobacco) plants and harvested leaves, utilizing novel transient expression systems. Advantages of the transient approach over in-planta production of enzymes in stably transformed plants are that it is rapid, can utilize wild type (non-transgenic) plant biomass, and that the plant growth and enzyme production stages are decoupled and can be separately optimized. Intellectual merit: This research project will improve fundamental bioprocess engineering understanding of transient agroinfiltration processes, plant viral amplicon expression systems, recovery and characterization of plant-made enzymes, scale-up considerations in transient agroinfiltration processes, and techno-economic and environmental assessment of alternative bioprocessing strategies for production of cellulase enzymes. Broader impact: The benefits of the proposed research to society are 1) cost-effective, energyefficient and environmentally-sound technologies that will not only be useful for the production of cellulase and hemicellulase enzymes to meet the U.S biofuels mandates but also lead to "greener" and more efficient bioproduction technologies for the industrial enzyme industry, 2)enhanced fundamental process understanding of recombinant protein production using transient agroinfiltration in plants which will accelerate growth of companies utilizing similar technologies for vaccine and therapeutics production, 3) broadening participation of women and underrepresented minorities through proactive recruitment and interdisciplinary research and educational training opportunities at the interface of plant science, biotechnology and bioprocess engineering, and 4) broad curricular impact by incorporating research findings into existing and new lecture and laboratory courses.