Metabolic engineering of Ralstonia eutropha for the biosynthesis of 2-hydroxyacid-containing polyhydroxyalkanoates

Si Jae Park, Young Ah Jang, Hyuk Lee, A. Reum Park, Jung Eun Yang, Jihoon Shin, Young Hoon Oh, Bong Keun Song, Jonggeon Jegal, Seung Hwan Lee, Sang Yup Lee

Research output: Contribution to journalArticlepeer-review

51 Scopus citations

Abstract

Polyhydroxyalkanoates (PHAs) are bio-based and biodegradable polyesters synthesized by numerous microorganisms. PHAs containing 2-hydroxyacids as monomer units have attracted much attention, but their production has not been efficient. Here, we metabolically engineered Ralstonia eutropha strains for the in vivo synthesis of PHAs containing 2-hydroxyacids as monomers. This was accomplished by replacing the R. eutropha phaC gene in the chromosome with either the R. eutropha phaC S506. G A510. K gene, which contains two point mutations, or the Pseudomonas sp. MBEL 6-19 phaC1437 gene. In addition, the R. eutropha phaAB genes in the chromosome were replaced with the Clostridium propionicum pct540 gene. All of the engineered R. eutropha strains produced PHAs containing 2-hydroxyacid monomers, including lactate and 2-hydroxybutyrate (2HB), along with 3-hydroxybutyrate (3HB) and/or 3-hydroxyvalerate (3HV), when they were cultured in nitrogen-free medium containing 5. g/L lactate or 4. g/L 2HB and 20. g/L glucose as carbon sources. Expression of the Escherichia coli ldhA gene in engineered R. eutropha strains allowed production of poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)] from glucose as the sole carbon source. This is the first report on the production of 2-hydroxyacid-containing PHAs by metabolically engineered R. eutropha.

Original languageEnglish
Pages (from-to)20-28
Number of pages9
JournalMetabolic Engineering
Volume20
DOIs
StatePublished - 2013

Keywords

  • 2-hydroxyacid
  • 2-hydroxybutyrate
  • Lactate
  • PHA
  • Ralstonia eutropha

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