Bioconversion of lime pretreated wheat straw to fuel ethanol

Authors: Saha, Badal; Cotta, Michael

Submitted to: UJNR Food & Agricultural Panel Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/21/2007
Publication Date: 10/21/2007
Citation: Saha, B.C., Cotta, M.A. 2007. Bioconversion of lime pretreated wheat straw to fuel ethanol. In: Proceedings of the U.S.-Japan Food and Agricultural Panel 36th Annual Meeting, October 21-25, 2007, Tsukuba, Ibaraki, Japan. p. 284-287.

Interpretive Summary:

Technical Abstract: Lime pretreatment and enzymatic saccharification methods were evaluated for conversion of wheat straw cellulose and hemicellulose to fermentable sugars. The maximum yield of monomeric sugars from wheat straw (8.6%, w/v) by lime pretreatment (100 mg/g straw, 121 deg C, 1 h) and enzymatic hydrolysis (45 deg C, pH 5.0, 120 h) using a cocktail of 3 commercial enzyme preparations (cellulase, beta-glucosidase, and xylanase) at the dose level of 0.15 ml of each enzyme preparation per g straw was 568 +/- 13 mg/g (82% yield). During the pretreatment, no measurable quantities of furfural and hydroxymethyl furfural were produced. The concentration of ethanol from lime pretreated enzyme saccharified wheat straw (78 g) hydrolyzate by recombinant Escherichia coli strain FBR5 at pH 6.5 and 35 deg C in 24 h was 22.5 +/- 0.6 g/L with a yield of 0.50 g/g available sugars (0.29 g/g straw). The ethanol concentration was 20.6 +/- 0.4 g/L with a yield of 0.26 g/g straw in the case of simultaneous saccharification and fermentation by the E. coli strain at pH 6.0 and 35 deg C in 72 h.