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Title: Consolidated bioprocessing of transgenic switchgrass by an engineered and evolved Clostridium thermocellum strain

Abstract

Background: Switchgrass is an abundant and dedicated bioenergy feedstock however its inherent recalcitrance is one of the economic hurdles for producing biofuels. The down-regulation of the caffeic acid O-methyl transferase (COMT) gene in the lignin pathway of switchgrass reduced lignin content and S/G ratio, and the transgenic lines showed improved fermentation yield with S. cerevisiae and C. thermocellum (ATCC 27405) in comparison to the wild-type switchgrass. Results: Here we examine the fermentation potential of the COMT transgenic switchgrass and its wild-type line, with an engineered and evolved Clostridium thermocellum (M1570) strain. The fermentation of the transgenic switchgrass had superior conversion relative to the control line with an increase of 20% and ethanol was the primary metabolite accounting for 90% of the total metabolites measured by HPLC. Conclusions: The down-regulation of the COMT gene in switchgrass reduced recalcitrance and improved microbial bioconversion yield. Moreover, these results showed ethanol as the main fermentation metabolite produced by an engineered and evolved C. thermocellum strain grown on a transgenic switchgrass.

Authors:
 [1];  [1];  [1];  [2];  [2];  [1];  [1]
  1. ORNL
  2. Noble Foundation
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1159464
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Biotechnology for Biofuels
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 1754--6834
Country of Publication:
United States
Language:
English
Subject:
SWITCHGRASS; CLOSTRIDIUM THERMOCELLUM; CELLULOSIC ETHANOL; Transgenic; switchgrass; metabolic engineering; Clostridium thermocellum; consolidated bioprocessing; feedstock; cellulosic ethanol

Citation Formats

Yee, Kelsey L, Rodriguez, Jr, Miguel, Thompson, Olivia A, Fu, Chunxiang, Wang, Zeng-Yu, Davison, Brian H, and Mielenz, Jonathan R. Consolidated bioprocessing of transgenic switchgrass by an engineered and evolved Clostridium thermocellum strain. United States: N. p., 2014. Web. doi:10.1186/1754-6834-7-75.
Yee, Kelsey L, Rodriguez, Jr, Miguel, Thompson, Olivia A, Fu, Chunxiang, Wang, Zeng-Yu, Davison, Brian H, & Mielenz, Jonathan R. Consolidated bioprocessing of transgenic switchgrass by an engineered and evolved Clostridium thermocellum strain. United States. https://doi.org/10.1186/1754-6834-7-75
Yee, Kelsey L, Rodriguez, Jr, Miguel, Thompson, Olivia A, Fu, Chunxiang, Wang, Zeng-Yu, Davison, Brian H, and Mielenz, Jonathan R. 2014. "Consolidated bioprocessing of transgenic switchgrass by an engineered and evolved Clostridium thermocellum strain". United States. https://doi.org/10.1186/1754-6834-7-75.
@article{osti_1159464,
title = {Consolidated bioprocessing of transgenic switchgrass by an engineered and evolved Clostridium thermocellum strain},
author = {Yee, Kelsey L and Rodriguez, Jr, Miguel and Thompson, Olivia A and Fu, Chunxiang and Wang, Zeng-Yu and Davison, Brian H and Mielenz, Jonathan R},
abstractNote = {Background: Switchgrass is an abundant and dedicated bioenergy feedstock however its inherent recalcitrance is one of the economic hurdles for producing biofuels. The down-regulation of the caffeic acid O-methyl transferase (COMT) gene in the lignin pathway of switchgrass reduced lignin content and S/G ratio, and the transgenic lines showed improved fermentation yield with S. cerevisiae and C. thermocellum (ATCC 27405) in comparison to the wild-type switchgrass. Results: Here we examine the fermentation potential of the COMT transgenic switchgrass and its wild-type line, with an engineered and evolved Clostridium thermocellum (M1570) strain. The fermentation of the transgenic switchgrass had superior conversion relative to the control line with an increase of 20% and ethanol was the primary metabolite accounting for 90% of the total metabolites measured by HPLC. Conclusions: The down-regulation of the COMT gene in switchgrass reduced recalcitrance and improved microbial bioconversion yield. Moreover, these results showed ethanol as the main fermentation metabolite produced by an engineered and evolved C. thermocellum strain grown on a transgenic switchgrass.},
doi = {10.1186/1754-6834-7-75},
url = {https://www.osti.gov/biblio/1159464}, journal = {Biotechnology for Biofuels},
issn = {1754--6834},
number = 1,
volume = 7,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 2014},
month = {Wed Jan 01 00:00:00 EST 2014}
}