ARS | Publication request: ON-FARM PRETREATMENT TECHNOLOGIES FOR IMPROVING ENZYMATIC DIGESTIBILITY OF CELLULOSE AND HEMICELLULOSE PRESENT IN PERENNIAL GRASS

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 29, 2007
Publication Date: June 17, 2007
Citation: Digman, M.F., Shinners, K.J., Dien, B.S., Hatfield, R.D., Li, X., Muck, R.E., Weimer, P.J. 2007. On-farm pretreatment technologies for improving enzymatic digestibility of cellulose and hemicellulose present in perennial grass. In: Proceedings of 2007 Annual Meeting of American Society of Agricultural and Biological Engineers, June 17, 2007, Minneapolis, Minnesota. Paper No. 071021.

Technical Abstract: This research investigated the ability of on-farm pretreatments with acid, alkali, ozone, or novel enzymes to improve enzymatic degradability of cellulose and hemicelluloses in biomass at the biorefinery. Two perennial grasses, switchgrass (Panicum virgatum) and reed canarygrass (Phalaris arundinacea L.) were direct-cut harvested, pretreated, and stored anaerobically for 30 days. Pretreated and untreated samples were fermented to ethanol by Saccharomyces cerevisiae in the presence of commercial cellulase for 72 hr to ethanol. Xylose yields were also measured following fermentation because xylose is not metabolized by S. cerevisiae. Sulfuric acid and lime pretreatment technologies look promising, considering the high conversion yields and ease of application. Efficiencies of nearly 80% for cellulose conversion to ethanol and hemicellulose to xylose were realized, albeit at high chemical loadings. Ozonolysis results demonstrated similar success, but integration of this technology into current storage systems will be challenging. Enzyme addition (xylanases or feruloyl esterase) at ensiling only marginally improved conversion efficiency.