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A modified pathway for the production of acetone in Escherichia coli

Paper ID Volume ID Publish Year Pages File Format Full-Text
31665 44827 2013 8 PDF Available
Title
A modified pathway for the production of acetone in Escherichia coli
Abstract

A modified synthetic acetone operon was constructed. It consists of two genes from Clostridium acetobutylicum (thlA coding for thiolase and adc coding for acetoacetate decarboxylase) and one from Bacillus subtilis or Haemophilus influenzae (teIIsrf or ybgC, respectively, for thioesterase). Expression of this operon in Escherichia coli resulted in the production of acetone starting from the common metabolite acetyl-CoA via acetoacetyl-CoA and acetoacetate. The thioesterases do not need a CoA acceptor for acetoacetyl-CoA hydrolysis. Thus, in contrast to the classic acetone pathway of Clostridium acetobutylicum and related microorganisms which employ a CoA transferase, the new pathway is acetate independent. The genetic background of the host strains was crucial. Only E. coli strains HB101 and WL3 were able to produce acetone via the modified plasmid based pathway, up to 64 mM and 42 mM in 5-ml cultures, respectively. Using glucose fed-batch cultures the concentration could be increased up to 122 mM acetone with HB101 carrying the recombinant plasmid pUC19ayt (thioesterase from H. influenzae). The formation of acetone led to a decreased acetate production by E. coli.

► The CoA-transferase of the classical clostridial acetone pathway was replaced by a thioesterase. ► The new acetone pathway is acetate independent. ► E. coli HB101 pUC19ayt produces higher acetone titers as compared to the classical ABE fermentation.

Keywords
Acetone; Thioesterase; E. coli
First Page Preview
A modified pathway for the production of acetone in Escherichia coli
Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 15, January 2013, Pages 218–225
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering