Document Detail

Engineered ketol-acid reductoisomerase and alcohol dehydrogenase enable anaerobic 2-methylpropan-1-ol production at theoretical yield in Escherichia coli.
MedLine Citation:
PMID:  21515217     Owner:  NLM     Status:  In-Data-Review    
2-methylpropan-1-ol (isobutanol) is a leading candidate biofuel for the replacement or supplementation of current fossil fuels. Recent work has demonstrated glucose to isobutanol conversion through a modified amino acid pathway in a recombinant organism. Although anaerobic conditions are required for an economically competitive process, only aerobic isobutanol production has been feasible due to an imbalance in cofactor utilization. Two of the pathway enzymes, ketol-acid reductoisomerase and alcohol dehydrogenase, require nicotinamide dinucleotide phosphate (NADPH); glycolysis, however, produces only nicotinamide dinucleotide (NADH). Here, we compare two solutions to this imbalance problem: (1) over-expression of pyridine nucleotide transhydrogenase PntAB and (2) construction of an NADH-dependent pathway, using engineered enzymes. We demonstrate that an NADH-dependent pathway enables anaerobic isobutanol production at 100% theoretical yield and at higher titer and productivity than both the NADPH-dependent pathway and transhydrogenase over-expressing strain. Our results show how engineering cofactor dependence can overcome a critical obstacle to next-generation biofuel commercialization.
Sabine Bastian; Xiang Liu; Joseph T Meyerowitz; Christopher D Snow; Mike M Y Chen; Frances H Arnold
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Metabolic engineering     Volume:  13     ISSN:  1096-7184     ISO Abbreviation:  Metab. Eng.     Publication Date:  2011 May 
Date Detail:
Created Date:  2011-04-25     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9815657     Medline TA:  Metab Eng     Country:  Belgium    
Other Details:
Languages:  eng     Pagination:  345-52     Citation Subset:  IM    
Copyright Information:
Copyright © 2011 Elsevier Inc. All rights reserved.
Division of Chemistry and Chemical Engineering, California Institute of Technology, Mail code 210-41, Pasadena, CA 91125, USA.
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