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Enzyme Research
Volume 2011, Article ID 340279, 6 pages
http://dx.doi.org/10.4061/2011/340279
Research Article

Bioconversion of Agricultural Waste to Ethanol by SSF Using Recombinant Cellulase from Clostridium thermocellum

1Department of Biotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
2Department of Biotechnology and Environmental Sciences, Thaper University, Bhadson Road, Patiala 140007, Punjab, India

Received 1 March 2011; Revised 20 May 2011; Accepted 21 May 2011

Academic Editor: Alane Beatriz Vermelho

Copyright © 2011 Ruchi Mutreja et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effect of different pretreatment methods, temperature, and enzyme concentration on ethanol production from 8 lignocellulosic agrowaste by simultaneous saccharification and fermentation (SSF) using recombinant cellulase and Saccharomyces cerevisiae were studied. Recombinant cellulase was isolated from E. coli BL21 cells transformed with CtLic26A-Cel5-CBM11 full-length gene from Clostridium thermocellum and produced in both batch and fed-batch processes. The maximum cell OD and specific activity in batch mode were 1.6 and 1.91 U/mg, respectively, whereas in the fed-batch mode, maximum cell OD and specific activity were 3.8 and 3.5 U/mg, respectively, displaying a 2-fold increase. Eight substrates, Syzygium cumini (jamun), Azadirachta indica (neem), Saracens indica (asoka), bambusa dendrocalmus (bamboo), Populas nigra (poplar), Achnatherum hymenoides (wild grass), Eucalyptus marginata (eucalyptus), and Mangifera indica (mango), were subjected to SSF. Of three pretreatments, acid, alkali, and steam explosion, acid pretreatment Syzygium cumini (Jamun) at 30°C gave maximum ethanol yield of 1.42 g/L.