title: Cellulosic ethanol production on temperature-shift simultaneous saccharification and fermentation using the thermostable yeast Kluyveromyces marxianus CHY1612.
abstract: In cellulosic ethanol production, use of simultaneous saccharification and fermentation (SSF) has been suggested as the favorable strategy to reduce process costs. Although SSF has many advantages, a significant discrepancy still exists between the appropriate temperature for saccharification (45-50 °C) and fermentation (30-35 °C). In the present study, the potential of temperature-shift as a tool for SSF optimization for bioethanol production from cellulosic biomass was examined. Cellulosic ethanol production of the temperature-shift SSF (TS-SSF) from 16 w/v% biomass increased from 22.2 g/L to 34.3 g/L following a temperature shift from 45 to 35 °C compared with the constant temperature of 45 °C. The glucose conversion yield and ethanol production yield in the TS-SSF were 89.3% and 90.6%, respectively. At higher biomass loading (18 w/v%), ethanol production increased to 40.2 g/L with temperature-shift time within 24 h. These results demonstrated that the temperature-shift process enhances the saccharification ratio and the ethanol production yield in SSF, and the temperature-shift time for TS-SSF process can be changed according to the fermentation condition within 24 h.
authors.affiliation: Changhae Institute of Cassava and Ethanol Research, Changhae Ethanol Co., LTD, Palbok-Dong 829, Dukjin-Gu, Jeonju, 561-203, South Korea.
authors.forename: Hyun-Woo
authors.initials: HW
authors.lastname: Kang
authors.forename: Yule
authors.initials: Y
authors.lastname: Kim
authors.forename: Seung-Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Gi-Wook
authors.initials: GW
authors.lastname: Choi
mesh_terms: D056804:Biofuels / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D002482:Cellulose / Q000378:metabolism*; D000431:Ethanol / Q000302:isolation & purification / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D007716:Kluyveromyces / Q000145:classification / Q000378:metabolism*; D013696:Temperature
chemical_list: D056804:Biofuels; D000431:Ethanol; D002482:Cellulose; D005947:Glucose