Pretreatment of Corn Stover by Low Moisture Anhydrous Ammonia (LMAA) in a Pilot-Scale Reactor and Bioconversion to Fuel Ethanol and Industrial Chemicals
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Corn stover (CS) adjusted to 50, 66, and 70 % moisture was pretreated by the low moisture anhydrous ammonia (LMAA) process in a pilot-scale ammoniation reactor. After ammoniation, the 70 % moisture CS was treated at 90 and 100 °C whereas the others were treated at 90 °C only. The 70 % moisture pretreated CS then was subjected to a storage study under non-sterile conditions for 3 months. It was found that storage time did not have significant effects on the compositions of the pretreated materials and their hydrolysis by commercial enzymes. The 70 % moisture CS treated at 90 °C was used for preparation of a mix sugar hydrolysate (MSH) using combination of cellulase and xylanase. The MSH was used to prepare a corn mash at 9.5 wt% solid then subjected to ethanol fermentation by Escherichia coli KO11. The 66 % moisture CS treated at 90 °C was hydrolyzed with xylanase to make a xylose-rich hydrolysate (XRH), which was subsequently used for butyric acid fermentation by Clostridium tyrobutyricum. The resultant cellulose-enriched residue was hydrolyzed with cellulase to make a glucose-rich hydrolysate (GRH), which was subsequently used for succinic acid fermentation by E. coli AFP184.
KeywordsCellulosic biomass Corn stover Pretreatment Low moisture anhydrous ammonia Ethanol Value-added products Fermentation
The authors would like to express their thanks the North Central Sun Grant Office for the financial support, DuPont Industrial Biosciences and Novozymes for providing the enzyme products, and Dr. Kurt Rosentrater of Iowa State University for obtaining the corn stover. The valuable assistance of Mr. Jacob Armiger and Mr. Paul Giardina on the experimental effort and sample analysis are also greatly appreciated.
- 1.Dale, B. E., & Holtzapple, M. (2015). The need for biofuels. Chemical Engineering Progress, 111, 36–44.Google Scholar
- 2.Anonymous (2014). World fuel ethanol production. Renewable Fuels Association (RFA). http://ethanolrfa.org/pages/World-Fuel-Ethanol-Production.
- 3.Drapcho, C. M., Nghiem, N. P., & Walker, T. H. (2008). Biofuels engineering process technology. New York: Mc-Graw-Hill.Google Scholar
- 4.Perlack, R. D., Wright, L. L., Turhollow, A. F., Graham, R. L., Stokes, B. J. and Erbach, D. C. (2005). Biomass as feedstock for bioenergy and bioproducts industry: the technical feasibility of a billion-ton annual supply. U. S. Department of Energy.Google Scholar
- 5.Werpy, T. and G. Petersen, G. (2004). Top value added chemicals from biomass, volume 1—results of screening for potential candidates from sugars and synthesis gas. U. S. Department of Energy.Google Scholar
- 9.Nghiem, N. P., Chon, N. M., Drapcho, C. M., & Walker, T. H. (2013). Sweet sorghum biorefinery for production of fuel ethanol and value-added co-products. Biological Engineering Transactions, 6, 143–155.Google Scholar
- 18.Sluiter, A., Hames, B., Ruiz, R., Scarlata, C., Sluiter, C., & Templeton, D. (2005). Determination of structural carbohydrates and lignin in biomass. National Renewable Energy Laboratory, Golden, CO.Google Scholar