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Homologous overexpression of xylanase in Fusarium oxysporum increases ethanol productivity during consolidated bioprocessing (CBP) of lignocellulosics

Paper ID Volume ID Publish Year Pages File Format Full-Text
24099 43497 2011 8 PDF Available
Title
Homologous overexpression of xylanase in Fusarium oxysporum increases ethanol productivity during consolidated bioprocessing (CBP) of lignocellulosics
Abstract

In an effort to increase ethanol productivity during the consolidated bioprocessing (CBP) of lignocellulosics by Fusarium oxysporum, we attempted the constitutive homologous overexpression of one of the key process enzymes, namely an endo-xylanase. The endo-β-1,4-xylanase 2 gene was incorporated into the F. oxysporum genome under the regulation of the gpdA promoter of Aspergillus nidulans. The transformation was effected through Agrobacterium tumefaciens and resulted in 12 transformants, two of which were selected for further study due to their high extracellular xylanase activities under normally repressing conditions (glucose as sole carbon source). During natural induction conditions (growth on xylan) though, the extracellular enzyme levels of the transformants were only marginally higher (5–10%) compared to the wild type despite the significantly stronger xylanase 2 mRNA signals. SDS-PAGE verified enzyme assay results that there was no intracellular xylanase 2 accumulation in the transformants, suggesting the potential regulation in a post transcriptional or translational level. The fermentative performance of the transformants was evaluated and compared to that of the wild type in simple CBP systems using either corn cob or wheat bran as sole carbon sources. Both transformants produced approximately 60% more ethanol compared to the wild type on corn cob, while for wheat bran this picture was repeated for only one of them. This result is attributed to the high extracellular xylanase activities in the transformants’ fermentation broths that were maintained 2–2.5-fold higher compared to the wild type.

Keywords
Fusarium oxysporum; Xylanase; Agrobacterium tumefaciens; Bioethanol; Lignocellulose; Consolidated bioprocessing
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Homologous overexpression of xylanase in Fusarium oxysporum increases ethanol productivity during consolidated bioprocessing (CBP) of lignocellulosics
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 152, Issues 1–2, 10 March 2011, Pages 16–23
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us