Co-expression of 3-ketoacyl-ACP reductase and polyhydroxyalkanoate synthase genes induces PHA production in Escherichia coli HB101 strain

Abstract

The Escherichia coli 3-ketoacyl-ACP reductase gene ( fabG Ec) was cloned using a PCR technique to investigate the metabolic link between fatty acid metabolism and polyhydroxyalkanoate (PHA) production. Three plasmids respectively harboring fabG Ec and the poly-3-hydroxyalkanoate synthesis genes phaC Ac and phaC1 Ps from Aeromonas caviae and Pseudomonas sp. 61-3 respectively were constructed and introduced into E. coli HB101 strain. On a two-stage cultivation using dodecanoate as the sole carbon source, recombinant E. coli HB101 strains harboring fabG Ec and phaC genes accumulated PHA copolymers (about 8 wt% of dry cell weight) consisting of several ( R)-3-hydroxyalkanoate units of C4, C6, C8, and C10. It has been suggested that overexpression of the fabG Ec gene leads to the supply of ( R)-3-hydroxyacyl-CoA for PHA synthesis via fatty acid degradation.