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Simultaneous saccharification and fermentation of Kanlow switchgrass pretreated by hydrothermolysis using Kluyveromyces marxianus IMB4
Author(s) -
Suryawati Lilis,
Wilkins Mark R.,
Bellmer Danielle D.,
Huhnke Raymond L.,
Maness Niels O.,
Banat Ibrahim M.
Publication year - 2008
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.21965
Subject(s) - kluyveromyces marxianus , kluyveromyces , fermentation , hydrolysis , food science , chemistry , yeast , microbiology and biotechnology , biology , biochemistry , saccharomyces cerevisiae
A thermotolerant yeast strain named Kluyveromyces marxianus IMB4 was used in a simultaneous saccharification and fermentation (SSF) process using Kanlow switchgrass as a feedstock. Switchgrass was pretreated using hydrothermolysis at 200°C for 10 min. After pretreatment, insoluble solids were separated from the liquid prehydrolyzate by filtration and washed with deionized water to remove soluble sugars and inhibitors. Insoluble solids were then hydrolyzed using a commercial cellulase preparation and the released glucose was fermented to ethanol by K. marxianus IMB4 in an SSF process. SSF temperature was 37, 41, or 45°C and pH was 4.8 or 5.5. SSF was conducted for 7 days. Results were compared with a control of Saccharomyces cerevisiae D 5 A at 37°C and pH 4.8. Fermentation by IMB4 at 45 and 41°C ceased after 3 and 4 days, respectively, when a pH 4.8 citrate buffer was used. Fermentation continued for all 7 days using IMB4 at 37°C and the control. When pH 5.5 citrate buffer was used, fermentation ceased after 96 h using IMB4 at 45°C, and ethanol yield was greater than when pH 4.8 citrate buffer was used (78% theoretical). Ethanol yield using IMB4 at 45°C, pH 5.5 was greater than the control after 48, 72, and 96 h ( P < 0.05). Biotechnol. Bioeng. © 2008 Wiley Periodicals, Inc.