Abstract
Current methods for measuring ethanol yields from lignocellulosic biomass are relatively slow and are not well geared for analyzing large numbers of samples generated by feedstock management and breeding research. The objective of this study was to determine if an in vitro ruminal fermentation assay used in forage quality research was predictive of results obtained using a conventional biomass-to-ethanol conversion assay. In the conventional assay, herbaceous biomass samples were converted to ethanol by Saccharomyces cerevisiae cultures in the presence of cellulase enzymes. Cultures were grown in sealed serum bottles and gas production monitored by measuring increasing head space pressure. Gas accumulation as calculated from the pressure measurements was highly correlated (r2>0.9) with ethanol production measured by gas chromatography at 24 h or 7 days. The same feedstocks were also analyzed by in vitro ruminal digestion, as also measured by gas accumulation. Good correlations (r2∼0.63–0.82) were observed between ethanol production during simultaneous saccharification and fermentation and gas accumulation in parallel in vitro ruminal fermentations. Because the in vitro ruminal fermentation assay can be performed without sterilization of the medium and does not require aseptic conditions, this assay may be useful for biomass feedstock agronomic and breeding research.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Beuvink JMW, Spoelstra SF (1992) Interactions between substrate, fermentation end-products, buffering systems and gas production upon fermentation of different carbohydrates by mixed rumen microorganisms in vitro. Appl Microbiol Biotechnol 37:505–509
Davies ZS, Mason D, Brooks AE, Griffith GW, Merry RW, Theodorou MK (2000) An automated system for measuring gas production from forages inoculated with rumen fluid and its use in determining the effect of enzymes on grass silage. Anim Feed Sci Technol 83:205–221
Dien BS, Bothast RJ, Iten LB, Barrios L, Eckhoff SR (2002) Fate of Bt protein and influence of corn hybrid on ethanol production. Cereal Chem 79:582–585
Goering HK, Van Soest PJ (1970) Forage fiber analysis: apparatus, reagents, procedures and some applications, Agriculture Handbook No. 379. Agricultural Research Service, United States Department of Agriculture. Washington
Lee MR, Brooks AE, Moorby JM, Humphreys MO, Theodorou MK, MacRae JC, Scollan ND (2002) In vitro investigation into the nutritive value of Lolium perenne bred for an elevated concentration of water-soluble carbohydrate and the added effect of sample processing: freeze-dried and ground vs frozen and thawed. Anim Res 51:269–277
Lynd LR, Weimer PJ, Pretorius IS, Van Zyl WH (2002) Microbial cellulose utilization: fundamentals and biotechnology. Microbiol Mol Biol Rev 66:506–577
Menke KH, Raab L, Salewski A, Steingass H, Fritz D, Scheider W (1979) An estimation of the digestibility and metabolizable energy content of ruminant feedstuffs from the gas production when they are incubated with rumen liquor in vitro. J Agric Sci 93:217–222
Mertens DR, Weimer PJ, Waghorn GC (1998) Inocula differences affect in vitro gas production kinetics. In: Deaville ER, Owen E, Adesogan AT, Huntington JG, Lawrence TLJ (eds) In vitro techniques for measuring nutrient supply to ruminants. Occasional Publication No.22, British Society for Animal Science, Edinburgh, UK, pp 95–97
Mourino F, Akkarawongsa R, Weimer PJ (2001) Initial pH as a determinant of cellulose digestion rate by mixed ruminal microorganisms in vitro. J Dairy Sci 84:848–859
Schofield P, Pell AN (1995) Validity of using accumulated gas pressure readings to measure forage digestion in vitro: a comparison involving three forages. J Dairy Sci 78:2230–2238
Shelton DR, Tiedje JM (1984) General method for determining anaerobic biodegradation potential. Appl Environ Microbiol 47:850–857
Theodorou MK, Williams BA, Dhanoa MS, McAllan AB, France J (1994) A simple gas production method using a pressure transducer to determine the fermentation kinetics of ruminant feeds. Anim Feed Sci Technol 48:185–197
United States Department of Energy (1995) SSF experimental protocols: cellulosic biomass hydrolysis and fermentation. Protocol LAP008. http://www.eere.energy.gov/biomass/analytical_procedures.html
Vogel KP, Brejda JJ, Walters DT, Buxton DR (2002) Switchgrass biomass production in the Midwest USA: harvest and nitrogen management. Agron J 94:413–419
Acknowledgements
We thank C.L. Odt, K. Darling, M. Larrison and P.J. O’Bryan for technical assistance during various aspects of this study. We also thank S. Selman for DM predictions by NIRS, and D.R. Mertens for helpful discussions
Author information
Authors and Affiliations
Corresponding author
Additional information
Disclaimer: Mention of specific products is for informational purposes only and does not imply a warranty or recommendation of such products to the exclusion of other products that may also be suitable.
Rights and permissions
About this article
Cite this article
Weimer, P.J., Dien, B.S., Springer, T.L. et al. In vitro gas production as a surrogate measure of the fermentability of cellulosic biomass to ethanol. Appl Microbiol Biotechnol 67, 52–58 (2005). https://doi.org/10.1007/s00253-004-1844-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00253-004-1844-7