Author(s)

Masahide Yasuda, Keisuke Takeo, Hayato Nagai, Takuya Uto, Toshifumi Yui, Tomoko Matsumoto, Yasuyuki Ishii, Kazuyoshi Ohta

Center for Collaborative Research and Community Cooperation, University of Miyazaki, Miyazaki, Japan.
Department of Animal and Grassland Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Miyazaki, Japan.
Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.

Napiegrass (Pennisetum purpureum Schumach) was treated with a low-moisture anhydrous ammonia (LMAA) pretreatment by adding an equal weight of water and keeping it under atmospheric ammonia gas at room temperature for four weeks. After the removal of ammonia and washing with water, a simultaneous saccharification and fermentation (SSF) was conducted for the LMAA-pretreated napiergrass (1.33 g) in a buffer solution (8 mL) using a mixture of a cellulase (80 mg) and a xylanase (53 mg) as well as the cell suspension (0.16 mL) of Saccharomyces cerevisiae. Ethanol and xylose resulted in 91.2% and 62.9% yields, respectively. The SSF process was scaled up using LMAA-pretreated napiergrass (100.0 g) to give ethanol (77.2%) and xylose (52.8%). After the removal of ethanol, the pentose fermentation of the SSF solution (40 mL), which contained 1.00 g of xylose, using cell suspension of Escherichia coli KO11 (70 mL) gave 86.3% yield of ethanol. Total ethanol yield reached 68.9% based on xylan (21.4 wt%) and glucan (39.7 wt%) of the LMAA-pretreated napiergrass.

LMAA; SSF; Cellulase; Xylanase; Saccharomyces cerevisiae; Escherichia coli KO11

Yasuda, M. , Takeo, K. , Nagai, H. , Uto, T. , Yui, T. , Matsumoto, T. , Ishii, Y. and Ohta, K. (2013) Enhancement of Ethanol Production from Napiergrass (Pennisetum purpureum Schumach) by a Low-Moisture Anhydrous Ammonia Pretreatment. Journal of Sustainable Bioenergy Systems, 3, 179-185. doi: 10.4236/jsbs.2013.33025.