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Ethanol production from water hyacinth (Eichhornia crassipes) hydrolysate by hyper-thermal acid hydrolysis, enzymatic saccharification and yeasts adapted to high concentration of xylose

Sunwoo, InYung, Kwon, Jeong Eun, Nguyen, Trung Hau, Jeong, Gwi-Tack, Kim, Sung-Koo
Bioprocess and biosystems engineering 2019 v.42 no.8 pp. 1367-1374
Clavispora lusitaniae, Eichhornia crassipes, Saccharomyces cerevisiae, Scheffersomyces stipitis, acid hydrolysis, ethanol, ethanol production, evolutionary adaptation, feedstocks, fermentation, hydrolysates, saccharification, slurries, sulfuric acid, xylose, yeasts
Water hyacinth (Eichhornia crassipes) was used as a feedstock for ethanol production. The optimal hyper-thermal (HT) acid hydrolysis conditions were 8% (w/v) slurry content, 200 mM H₂SO₄, at 160 °C for 20 min and enzymatic saccharification for 48 h using an enzyme mixture of 20 units/mL Viscozyme L and Cellic C Tec2. After pretreatment, 48.2 g/L monosaccharides were obtained. Fermentation was conducted with wild and adapted Saccharomyces cerevisiae, Pichia stipitis and Candida lusitaniae. Wild-type S. cerevisiae, P. stipitis, and C. lusitaniae produced 15.3, 19.5 and 22.7 g/L of ethanol, respectively. Adaptive evolution was carried out on 6% (w/v) xylose. S. cerevisiae, P. sipitis and C. lusitaniae adapted to xylose produced 15.3, 21.4 and 23.9 g/L of ethanol with YEₜOH of 0.32, 0.44 and 0.49, respectively. These results indicate that water hyacinth has potential as a feed stock for ethanol.