Nitric-acid hydrolysis of Miscanthus giganteus to sugars fermented to bioethanol
- 197 Downloads
Miscanthus giganteus (M. giganteus) is a promising feedstock for the production of bioethanol or biochemicals. Using only dilute nitric acid, this work describes a two-step process for hydrolyzing hemicellulose and cellulose to fermentable sugars. Primary variables were temperature and reaction time. The solid-to-liquid mass ratio was 1:8. No enzymes were used. In the first step, M. giganteus was contacted with 0.5 wt.% nitric acid at temperatures between 120 and 160°C for 5 to 40 min. The second step used 0.5 or 0.75 wt.% nitric acid at temperatures between 180 and 210°C for less than 6 min. Under selected conditions, almost all hemicellulose and 58% cellulose were transferred to the liquid phase. Small amounts of degradation products were observed. The xylose solution obtained from the nitric-acid hydrolysis was fermented for 96 h and the glucose solution for 48 h to yield 0.41 g ethanol/g xylose and 0.46 g ethanol/g glucose. To characterize residual solids and the liquor from both steps, nuclear-magneticresonance (NMR) spectroscopy was performed for each fraction. The analytical data indicate that the liquid phase from Steps 1 and 2 contain little lignin or lignin derivatives.
KeywordsMiscanthus giganteus dilute-nitric-acid hydrolysis two-step process fermentation analysis with NMR
Unable to display preview. Download preview PDF.
- 6.Liu, Z., S. Padmanabhan, K. Cheng, H. Xie, A. Gokhale, W. Afzal, H. Na, M. Pauly, A. T. Bell, and J. M. Prausnitz (2014) Two-step delignification of miscanthus to enhance enzymatic hydrolysis: Aqueous ammonia followed by sodium hydroxide and oxidants. Energy Fuels. 28: 542–548.CrossRefGoogle Scholar
- 7.Yu, G., W. Afzal, F. Yang, S. Padmanabhan, Z. Liu, H. Xie, M. A. Shafy, A. T. Bell, and J. M. Prausnitz (2014) Pretreatment of miscanthus×giganteus using aqueous ammonia with hydrogen peroxide to increase enzymatic hydrolysis to sugars. J. Chem. Technol. Biotechnol. 89: 698–706.CrossRefGoogle Scholar
- 10.Taherzadeh, M. J. and K. Karimi (2007) Acid-based hydrolysis processes for ethanol from lignocellulosic materials: A review. BioResources. 2: 472–499.Google Scholar
- 20.Brink, D. L. (1996) Hydrolyzing lignocellulose. US Patent 5,536,325.Google Scholar
- 21.Brink, D. L. (1993) Two stage hydrolysis or depolymerization of polysaccharide material as cellulose, hemicellulose and lignocellulose to monosaccharides using nitric acid. US Patent 5,221,357.Google Scholar
- 22.Brink, D. L. (1994) Method of treating biomass material. US Patent 5,366,558.Google Scholar
- 23.Sluiter, A., B. Hames, R. Ruiz, C. Scarlata, J. Sluiter, D. Templeton, and D. Crocker (2008) Determination of Structural Carbohydrates and Lignin in Biomass. National Renewable Energy Laboratory, Golden, CO, USA.Google Scholar
- 25.Kim, S. R., J. M. Skerker, W. Kang, A. Lesmana, N. Wei, A. P. Arkin, and Y. S. Jin (2013) Rational and evolutionary engineering approaches uncover a small set of genetic changes efficient for rapid xylose Fermentation in Saccharomyces cerevisiae. Plos One 8: 13.Google Scholar
- 30.Lewis Liu, Z., J. Moon, B. Andersh, P. Slininger, and S. Weber (2008) Multiple gene-mediated NAD(P)H-dependent aldehyde reduction is a mechanism of in situ detoxification of furfural and 5-hydroxymethylfurfural by Saccharomyces cerevisiae. Appl. Microbiol. Biotechnol. 81: 743–753.CrossRefGoogle Scholar