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Title: Expression of a heat-stable NADPH-dependent alcohol dehydrogenase from Thermoanaerobacter pseudethanolicus 39E in Clostridium thermocellum 1313 results in increased hydroxymethylfurfural resistance

Resistance to deconstruction is a major limitation to the use of lignocellulosic biomass as a substrate for the production of fuels and chemicals. Consolidated bioprocessing (CBP), the use of microbes for the simultaneous hydrolysis of lignocellulose into soluble sugars and fermentation of the resulting sugars to products of interest, is a potential solution to this obstacle. The pretreatment of plant biomass, however, releases compounds that are inhibitory to the growth of microbes used for CBP. Heterologous expression of the Thermoanaerobacter pseudethanolicus 39E bdhA gene, that encodes an alcohol dehydrogenase, in Clostridium thermocellum significantly increased resistance to furan derivatives at concentrations found in acid-pretreated biomass. The mechanism of detoxification of hydroxymethylfurfural was shown to be primarily reduction using NADPH as the cofactor. In addition, we report the construction of new expression vectors for homologous and heterologous expression in C. thermocellum. These vectors use regulatory signals from both C. bescii (the S-layer promoter) and C. thermocellum (the enolase promoter) shown to efficiently drive expression of the BdhA enzyme. Toxic compounds present in lignocellulose hydrolysates that inhibit cell growth and product formation are obstacles to the commercialization of fuels and chemicals from biomass. Lastly, expression of genes that reduce the effect of thesemore » inhibitors, such as furan derivatives, will serve to enable commercial processes using plant biomass for the production of fuels and chemicals.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of Georgia, Athens, GA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Report Number(s):
NREL/JA-2700-68259
Journal ID: ISSN 1754-6834
Grant/Contract Number:
AC36-08GO28308; AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Biotechnology for Biofuels
Additional Journal Information:
Journal Volume: 10; Journal Issue: 1; Journal ID: ISSN 1754-6834
Publisher:
BioMed Central
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; consolidated bioprocessing; Clostridium thermocellum; butanol dehydrogenase; furfural; 5-hydroxymethyl-2-furfural
OSTI Identifier:
1350020
Alternate Identifier(s):
OSTI ID: 1361373