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Engineering Escherichia coli with acrylate pathway genes for propionic acid synthesis and its impact on mixed-acid fermentation.
MedLine Citation:
PMID:  22810300     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Fermentation-derived products are in greater demand to meet the increasing global market as well as to overcome environmental problems. In this work, Escherichia coli has been metabolically engineered with acrylate pathway genes from Clostridium propionicum for the conversion of D: -lactic acid to propionic acid. The introduced synthetic pathway consisted of seven genes encoding the enzymes propionate CoA-transferase (Pct), lactoyl-CoA dehydratase (Lcd) and acryloyl-CoA reductase (Acr). The engineered strain synthesised propionic acid at a concentration of 3.7 ± 0.2 mM upon fermentation on glucose. This low production level could be attributed to the low activity of the recombinant enzymes in particular the rate-limiting enzyme, Acr. Interestingly, the recombinant pathway caused an increased lactate production in E. coli with a yield of 1.9 mol/mol of glucose consumed along with a decrease in other by-products. Down-regulation of the pfl (pyruvate formate lyase) genes and a possible inhibition of Pfl activity by the acrylate pathway intermediate, acryloyl-CoA, could have reduced carbon flow to the Pfl pathway with a concomitant increase in lactate production. This study reports a novel way of synthesising propionic acid by employing a non-native, user-friendly organism through metabolic engineering.
Authors:
Vijayalakshmi Kandasamy; Hema Vaidyanathan; Ivana Djurdjevic; Elamparithi Jayamani; K B Ramachandran; Wolfgang Buckel; Guhan Jayaraman; Subramanian Ramalingam
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-7-19
Journal Detail:
Title:  Applied microbiology and biotechnology     Volume:  -     ISSN:  1432-0614     ISO Abbreviation:  -     Publication Date:  2012 Jul 
Date Detail:
Created Date:  2012-7-19     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8406612     Medline TA:  Appl Microbiol Biotechnol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Centre for Biotechnology, Anna University, Chennai, 600 025, Tamil Nadu, India.
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