Biosynthesis of poly(4-hydroxybutyric acid) by recombinant strains of Escherichia coli

FEMS Microbiol Lett. 1997 Aug 15;153(2):411-8. doi: 10.1111/j.1574-6968.1997.tb12604.x.

Abstract

The aim of this study was the production of the homopolyester poly(4-hydroxybutyric acid) (poly(4HB)) with recombinant strains of Escherichia coli. Wild-type strains and other widely used non-recombinant strains of E. coli are not able to produce polyhydroxyalkanoic acids (PHA) as storage compounds and cannot utilize 4-hydroxybutyric acid as sole carbon source. Accordingly, hybrid plasmids of pBluescript vectors were constructed which harbored the Alcaligenes eutrophus PHA synthase gene (phaC) and the Clostridium kluyveri orfZ putatively encoding a 4-hydroxybutyric acid-coenzyme A transferase. A 3.5-kb genomic SmaI/ApaI fragment from A. eutrophus, which comprises phaC, and a 1.8-kb genomic ApaI/EcoRI fragment from C kluyveri, which contained orfZ, were inserted into the SmaI and EcoRI sites of the vectors pKS- and pSK-, respectively. The two resulting plasmids pSKSE5.3 and pKSSE5.3 comprising phaC and orfZ colinear or antilinear to lacZ, respectively, were transformed into E. coli XL1-Blue. Recombinant strains synthesized the homopolyester poly(4HB), when the cells were cultivated in Luria-Bertani broth and if glucose and 4-hydroxybutyric acid were provided as carbon sources. If glucose was omitted, a copolyester of 3-hydroxybutyric acid and 4-hydroxybutyric acid was accumulated. The homopolyester poly(4HB) was also accumulated during cultivation of these strains in M9 mineral salts medium containing glucose plus 4-hydroxybutyric acid as carbon sources. Poly(4HB) could amount up to approximately 80% (w/w) of the cell dry matter if E. coli XL1-Blue harboring pKSSE5.3 was cultivated in M9 mineral salts medium and if the cultures were not sufficiently supplied with oxygen. 4HB was also incorporated into PHA if gamma-butyrolactone was used as carbon source. If levulinic acid, 4-hydroxyvaleric acid or gamma-valerolactone were used as carbon sources, only very low amounts of PHA were accumulated which did not contain 4-hydroxyalkanoic acids as constituents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Butyrolactone / metabolism
  • Acetyl-CoA C-Acyltransferase / genetics
  • Acyltransferases / genetics
  • Coenzyme A-Transferases / genetics
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Genes, Bacterial / genetics
  • Glucose / metabolism
  • Hydroxybutyrates / metabolism
  • Lactones / metabolism
  • Levulinic Acids / metabolism
  • Polyesters / metabolism*
  • Recombinant Fusion Proteins
  • Sodium Oxybate / metabolism*
  • Succinates / metabolism
  • Valerates / metabolism

Substances

  • Hydroxybutyrates
  • Lactones
  • Levulinic Acids
  • Polyesters
  • Recombinant Fusion Proteins
  • Succinates
  • Valerates
  • poly(4-hydroxybutanoate)
  • poly-beta-hydroxybutyrate
  • Sodium Oxybate
  • Acyltransferases
  • poly-beta-hydroxybutyrate polymerase
  • Acetyl-CoA C-Acyltransferase
  • 4-hydroxybutyrate CoA-transferase
  • Coenzyme A-Transferases
  • Glucose
  • gamma-valerolactone
  • 4-Butyrolactone
  • levulinic acid