Abstract
Biorefineries that rely on lignocellulosic feedstocks require dependable and safe methods for storing biomass. Storing biomass wet in the presence of sulfuric acid and the absence of oxygen has been shown to preserve carbohydrates and enhance cellulose conversion but has not been demonstrated at farm-scale. To that end, switchgrass (Panicum virgatum L.) and reed canarygrass (Phalaris arundinacea L.) were pretreated with 18 N sulfuric acid with two methods: during bagging (on-line) and thoroughly mixed in a commercial feed mixer (mixed) and both stored for 90 days. The two methods, applied at rates from 28 to 54 g(kg DM)−1 not only helped to preserve biomass substrates under on-farm conditions (anaerobic, ambient temperature and pressure) through inhibition of microbial activity but also enhanced conversion of cellulose to ethanol by simultaneous saccharification and fermentation (SSF) using Saccharomyces cerevisiae. Acid-pretreated substrate yielded 19 and 7 percentage points higher ethanol conversion efficiencies than fresh reed canarygrass and switchgrass, respectively. The on-line method of pretreatment out-yielded the mixed method both as a preservative and as an agent for enhanced cell wall degradation. This result was thought to be an outcome of more uniform acid application as indicated by the on-line method’s more consistent pH profile and decreased fermentation products, as compared to the mixed method. Although significant levels of acetate and lactate were present in the biomass following storage, concentrations were not sufficient to inhibit S. cerevisiae in SSFs with a 10% solids loading.
Similar content being viewed by others
References
Hess JR, Wright CT, Kenney KL (2007) Cellulosic biomass feedstocks and logistics for ethanol production. Biofuels Bioproducts Biorefining-Biofpr 1:181–190
Shinners KJ, Binversie BN, Savoie P (2003) Whole-plant corn harvesting for biomass: comparison of single-pass and multiple-pass harvest systems. ASAE Annual International Meeting, Las Vegas
Shinners KJ, Boettcher GC (2006) Drying, harvesting and storage characteristics of perennial grasses as biomass feedstocks. ASABE Annual International Meeting, Minneapolis
Chen Y, Sharma-Shivappa RR, Chen C (2007) Ensiling agricultural residues for bioethanol production. Appl Biochem Biotechnol 143:80–92
Richard TL, Proulx S, Moore KJ, Shouse S (2001) Ensilage technology for biomass pre-treatment and storage. ASAE Annual International Meeting, Sacramento
Shinners KJ, Binversie BN, Muck RE, Weimer PJ (2007) Comparison of wet and dry corn stover harvest and storage. Biomass Bioenergy 31:211–221
Digman MF, Shinners KJ, Dien BS, Muck RE, Xin-Liang L, Hatfield RD, Weimer PJ (2007) On-farm pretreatment technologies for improving enzymatic degradability of cellulose and hemicellulose present in perennial grass. ASABE Annual International Meeting, Minneapolis, MN
Ren H, Richard TL, Moore KJ, Patrick P (2004) Long-term kinetics of corn stover bioconversion in an enzyme enhanced mixed culture fermentation. ASAE/CSAE Annual International Meeting, Ottawa, ON
Ren HY, Richard TL, Chen ZL, Kuo ML, Bian YL, Moore KJ, Patrick P (2006) Ensiling corn stover: effect of feedstock preservation on particleboard performance. Biotechnol Prog 22:78–85
Ren HY, Richard TL, Moore KJ (2007) The impact of enzyme characteristics on corn stover fiber degradation and acid production during ensiled storage. Appl Biochem Biotechnol 137:221–238
ASABE (2008) Moisture measurment—forages. St. Joseph, MI
ASABE (2007) Method of determining and expressing particle size of chopped forage materials by screening. St. Joseph, MI
Digman MF, Shinners KJ, Casler MD, Dien BS, Hatfield RD, Jung H-JG, Muck RE, Weimer PJ Optimizing on-farm pretreatment of perennial grasses for fuel ethanol production. Bioresource Technology In Press, Corrected Proof
Muck RE, Dickerson JT (1988) Storage-temperature effects on proteolysis in alfalfa silage. Trans ASAE 31:1005–1009
Dowe N, McMillan J (2001) Experimental protocols: lignocellulosic biomass hydrolysis and fermentation. National Renewable Energy Center, Golden, CO
Muck RE, Holmes BJ (2000) Factors affecting bunker silo densities. Appl Eng Agric 16:613–619
Muck RE, Holmes BJ (2006) Bag silo densities and losses. Trans ASABE 49:1277–1284
Pitt RE, Muck RE (1993) A diffusion model of aerobic deterioration at the exposed face of bunker silos. J Agric Eng Res 55:11–26
Chesson A (1981) Effects of sodium-hydroxide on cereal straws in relation to the enhanced degradation of structural polysaccharides by rumen microorganisms. Journal of the Science of Food and Agriculture 32:745–758
McDonald P (1981) The Biochemistry of Silage. Wiley, New York, NY
McDonald P (1981) Lactic acid bacteria. The biochemistry of silage. Wiley, New York, pp 62–76
Muck RE (1988) Factors influencing silage quality and their implications for management. J Dairy Sci 71:2992–3002
Digman MF, Shinners KJ, Dien BS, Hatfield RD, Muck RE, Weimer PJ (2008) Investigation of a two-stage process for increasing yields of ethanol from switchgrass. ASABE Annual International Meeting, Providence, RI
Acknowledgments
We acknowledge the support of Michael Boettcher, Rachel Digman, Patricia O'Bryan, and Christine Odt for their technical support and expertise. A special thanks to the farm crews at the Arlington Agricultural Research Station and United States Dairy Forage Research Farm for facilitating our research efforts. Finally, I would like to thank my committee members Kenneth Albrecht, Bruce Dien, Ronald Hatfield, Richard Muck, Xuejun Pan, Kevin Shinners for their guidance and expertise.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Digman, M.F., Shinners, K.J., Muck, R.E. et al. Full-scale On-farm Pretreatment of Perennial Grasses with Dilute Acid for Fuel Ethanol Production. Bioenerg. Res. 3, 335–341 (2010). https://doi.org/10.1007/s12155-010-9092-4
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12155-010-9092-4