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Simultaneous saccharification and fermentation of steam exploded duckweed: Improvement of the ethanol yield by increasing yeast titre

Author:
Zhao, X., Moates, G.K., Elliston, A., Wilson, D.R., Coleman, M.J., Waldron, K.W.
Source:
Bioresource technology 2015 v.194 pp. 263-269
ISSN:
0960-8524
Subject:
Lemna minor, beta-glucosidase, bioethanol, biomass, endo-1,4-beta-glucanase, ethanol, fermentation, inoculum, saccharification, steam, yeasts
Abstract:
This study investigated the conversion of Lemna minor biomass to bioethanol. The biomass was pre-treated by steam explosion (SE, 210°C, 10min) and then subjected to simultaneous saccharification and fermentation (SSF) using Cellic® CTec 2 (20U or 0.87FPUg−1 substrate) cellulase plus β-glucosidase (2Ug−1 substrate) and a yeast inoculum of 10% (v/v or 8.0×107cellsmL−1). At a substrate concentration of 1% (w/v) an ethanol yield of 80% (w/w, theoretical) was achieved. However at a substrate concentration of 20% (w/v), the ethanol yield was lowered to 18.8% (w/w, theoretical). Yields were considerably improved by increasing the yeast titre in the inoculum or preconditioning the yeast on steam exploded liquor. These approaches enhanced the ethanol yield up to 70% (w/w, theoretical) at a substrate concentration of 20% (w/v) by metabolising fermentation inhibitors.
Agid:
5366471