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Alkaline Peroxide Pretreatment of Corn Stover for Enzymatic Saccharification and Ethanol Production

Author:
Saha, Badal C., Cotta, Michael A.
Source:
Industrial biotechnology 2014 v.10 no.1 pp. 34
ISSN:
1550-9087
Subject:
Escherichia coli, alkali treatment, bacteria, cellulose, corn stover, ethanol, ethanol production, fermentation, hemicellulose, hydrogen peroxide, lignin, pH, saccharification, sugars
Abstract:
Alkaline hydrogen peroxide (AHP) pretreatment and enzymatic saccharification were evaluated for conversion of corn stover cellulose and hemicellulose to fermentable sugars. Corn stover used in this study contained 37.0±0.2% cellulose, 26.8±0.2% hemicellulose and 18.0±0.1% lignin on dry basis. Under the optimum conditions of AHP pretreatment [2% H2O2 (v/v), pH 11.5, 35oC, 24 h] of corn stover (10%, w/v) and enzymatic saccharification (45oC, pH 5.0, 72 h) with 0.1% (w/v) Tween 20, a total of 558±7 mg of fermentable sugars was obtained per g stover which is equivalent to 79.5% of theoretical sugar yield. Most of the lignin (82%) was removed from corn stover. The AHP pretreated and enzymatically saccharified corn stover hydrolyzate was fermented by recombinant Escherichia coli strain FBR 5 at pH 6.5 and 37oC for 96 h to produce 23.9±0.9 g ethanol from 56.6±1.6 g total sugars per L with an ethanol yield of 0.42 g/g available sugars and 0.24 g/g corn stover which is equivalent to 67% of theoretical ethanol yield from corn stover. The strain produced 25.0±0.3 g ethanol per L in 120 h from AHP pretreated corn stover (10%, w/v) by simultaneous saccharification and fermentation at pH 6.0 and 37oC with a yield of 0.25 g/g stover. This is the first report on the production of ethanol from AHP pretreated corn stover by a recombinant bacterium.
Agid:
58564
Handle:
10113/58564