METABOLIC ROUTING TOWARDS POLYHYDROXYALKANOIC ACID SYNTHESIS IN RECOMBINANT ESCHERICHIA-COLI (FADR) - INHIBITION OF FATTY-ACID BETA-OXIDATION BY ACRYLIC-ACID

Heterologous expression of the phaC1 gene from Pseudomonas aeruginosa, which encodes one of the polyhydroxyalkanoic acid synthases, in Esche richia coli impaired in fatty acid beta-oxidation results in polyhydro xyalkanoic acid accumulation when cells were cultivated on fatty acids . We evaluated the application of the fatty acid beta-oxidation inhibi tor acrylic acid as a tool to channel intermediates of beta-oxidation to polyhydroxyalkanoic acid synthesis. Various E. coli strains affecte d in fatty acid metabolism and the wild-type strain harboring plasmid pBHR71 were analyzed with respect to polyhydroxyalkanoic acid accumula tion in the presence of acrylic acid. The E. coli fadR mutant RS3097 r evealed the strongest polyhydroxyalkanoic acid accumulation. The optim um inhibitory concentration of acrylic acid was 0.24 mg ml(-1) and cau sed efficient channeling of intermediates of beta-oxidation to polyhyd roxyalkanoic acid synthesis. Under these conditions and grown on decan oate E. coli RS3097 harboring plasmid pBHR71 revealed a polyhydroxyalk anoic acid accumulation contributing to about 60% of cellular dry weig ht. (C) 1998 Federation of European Microbiological Societies. Publish ed by Elsevier Science B.V. All rights reserved.