Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa

Dogaris, J. and Gkounta, O. and Mamma, D. and Kekos, D. (2012) Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa. Applied Microbiology and Biotechnology . pp. 1-10.

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Bioethanol production from sweet sorghum bagasse (SB), the lignocellulosic solid residue obtained after extraction of sugars from sorghum stalks, can further improve the energy yield of the crop. The aim of the present work was to evaluate a cost-efficient bioconversion of SB to ethanol at high solids loadings (16 % at pretreatment and 8 % at fermentation), low cellulase activities (1–7 FPU/g SB) and co-fermentation of hexoses and pentoses. The fungus Neurospora crassa DSM 1129 was used, which exhibits both depolymerase and co-fermentative ability, as well as mixed cultures with Saccharomyces cerevisiae 2541. A dilute-acid pretreatment (sulfuric acid 2 g/100 g SB; 210 °C; 10 min) was implemented, with high hemicellulose decomposition and low inhibitor formation. The bioconversion efficiency of N. crassa was superior to S. cerevisiae, while their mixed cultures had negative effect on ethanol production. Supplementing the in situ produced N. crassa cellulolytic system (1.0 FPU/g SB) with commercial cellulase and β-glucosidase mixture at low activity (6.0 FPU/g SB) increased ethanol production to 27.6 g/l or 84.7 % of theoretical yield (based on SB cellulose and hemicellulose sugar content). The combined dilute-acid pretreatment and bioconversion led to maximum cellulose and hemicellulose hydrolysis 73.3 % and 89.6 %, respectively.

Item Type: Article
Additional Information: This work has been funded by the project PENED 2003. The project is cofinanced 80 % of public expenditure through EC-European Social Fund, 20 % of public expenditure through Ministry of Development—General Secretariat of Research and Technology and through private sector, under measure 8.3 of OPERATIONAL PROGRAMME “COMPETITIVENESS” in the 3rd Community Support Programme. The authors would like to thank Novozymes Corporation for generously providing the cellulase enzyme samples.
Author Affiliation: Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens,
Subjects: Plant Protection
Plant Physiology and Biochemistry > Biochemistry
Divisions: Sorghum
Depositing User: Mr. SanatKumar Behera
Date Deposited: 15 May 2012 03:29
Last Modified: 15 May 2012 03:29
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