title: Conversion of steam-exploded cedar into ethanol using simultaneous saccharification, fermentation and detoxification process.
abstract: In this study, we investigated the simultaneous saccharification, fermentation and detoxification SSDF process of steam-exploded cedar using a detoxification microorganism, Ureibacillus thermosphaericus A1, to facilitate efficient ethanol production. Steam explosion was applied as a pretreatment before enzymatic saccharification followed by alcohol fermentation. The highest glucose conversion rate was observed in the sample pretreated with a steam pressure of 45atm for 5min. Alcohol production by a heat-tolerant yeast, Saccharomyces cerevisiae BA11, was inhibited strongly by inhibitory materials present in the steam-exploded cedar, such as formic acid, furfural, and 5-hydroxymethylfurfural. The maximum amount of ethanol, i.e., 0.155g ethanol/g dry steam-exploded cedar, which corresponded to 74% of the theoretical ethanol yield, was obtained using the SSDF when U. thermosphaericus A1 degraded the inhibitory materials. A fed batch SSDF culture, in which U. thermosphaericus A1 was used to maintain low concentrations of inhibitory materials, was effective for increasing the ethanol concentration.
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Asada
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan.
authors.forename: Chizuru
authors.initials: C
authors.lastname: Sasaki
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Takamatsu
authors.affiliation: Department of Life System, Institute of Technology and Science, The University of Tokushima, 2-1 Minamijosanjima-cho, Tokushima 770-8506, Japan. Electronic address: ynakamu@bio.tokushima-u.ac.jp.
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D056449:Bacillales / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D028203:Cedrus / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D059205:Renewable Energy; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014934:Wood / Q000378:metabolism*
chemical_list: D000431:Ethanol; D005947:Glucose
keywords: Cedar; Saccharomyces cerevisiae BA11; Simultaneous saccharification and fermentation; Steam explosion; Ureibacillus thermosphaericus A1