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.
- miscanthus giganteus
- dilute-nitric-acid hydrolysis
- two-step process
- analysis with NMR
Yang, F., Afzal, W., Cheng, K., Liu, N., Pauly, M., Bell, A. T., ... Prausnitz, J. M. (2015). Nitric-acid Hydrolysis of Miscanthus giganteus to Sugars Fermented to Bioethanol. Biotechnology and Bioprocess Engineering, 20(2), 304-314. https://doi.org/10.1007/s12257-014-0658-4