TITLE:
Enhancement of Ethanol Production from Napiergrass (Pennisetum purpureum Schumach) by a Low-Moisture Anhydrous Ammonia Pretreatment
AUTHORS:
Masahide Yasuda, Keisuke Takeo, Hayato Nagai, Takuya Uto, Toshifumi Yui, Tomoko Matsumoto, Yasuyuki Ishii, Kazuyoshi Ohta
KEYWORDS:
LMAA; SSF; Cellulase; Xylanase; Saccharomyces cerevisiae; Escherichia coli KO11
JOURNAL NAME:
Journal of Sustainable Bioenergy Systems,
Vol.3 No.3,
September
13,
2013
ABSTRACT: 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.