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Disruption of lactate dehydrogenase through homologous recombination to improve bioethanol production in Thermoanaerobacterium aotearoense

Paper ID Volume ID Publish Year Pages File Format Full-Text
17473 42671 2011 7 PDF Available
Title
Disruption of lactate dehydrogenase through homologous recombination to improve bioethanol production in Thermoanaerobacterium aotearoense
Abstract

To enhance ethanol production in Thermoanaerobacterium aotearoense, the lactate dehydrogenase (ldh) gene, which is responsible for lactic acid production in a key branch pathway, was successfully disrupted via homologous recombination. ldh-up and ldh-down were designed and amplified based on JW/SL-YS485-AY 278026, and they were subsequently used as homologous fragments with an inserted erythromycin resistance gene to construct the targeted vector based on pBLUESCRIPT II SK(+). Southern hybridization and PCR-based assay definitely confirmed that the ldh gene in the Δldh mutant was disrupted by the insertion of the erythromycin resistance gene. Compared with the wild type, the Δldh mutant exhibited increases of 31.0% and 31.4% in cell yield under glucose and xylose cultivation, respectively, probably because knocking out the ldh gene results in increased acetate and ATP levels. Knockout of lactate dehydrogenase produced 2.37- and 2.1-fold increases in the yield of ethanol (mole/mole substrate) under glucose and xylose cultivation, respectively. Moreover, no lactic acid was detected in Δldh mutant fermentation mixtures (detection limit of HPLC: 0.5 mM), but lactic acid was readily detected for growth of the wild-type strain on both glucose and xylose, with final concentrations up to 59.24 mM and 56.06 mM, respectively. The success of this process thoroughly demonstrates the methodological possibility of gene knockout through homologous recombination in Thermoanaerobacterium.

Keywords
Ethanol; Homologous recombination; Lactate dehydrogenase; Thermoanaerobacterium aotearoense
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Disruption of lactate dehydrogenase through homologous recombination to improve bioethanol production in Thermoanaerobacterium aotearoense
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 48, Issue 2, 8 February 2011, Pages 155–161
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