Polyhydroxyalkanoate accumulation in Burkholderia sp.: a molecular approach to elucidate the genes involved in the formation of two homopolymers consisting of short-chain-length 3-hydroxyalkanoic acids

• Published in: Applied microbiology and biotechnology 2000-04, Vol.53 (4), p.453-460
• Main Authors: DE ANDRADE RODRIGUES, M. F, VALENTIN, H. E, BERGER, P. A, TRAN, M, ASRAR, J, GRUYS, K. J, STEINBÜCHEL, A
• Format: Article
• Language: English
• Subjects: 3-Hydroxy-4-pentenoic acid; Accumulation; acetoacetyl-CoA reductase; Acyltransferases - chemistry; Acyltransferases - genetics; Amino Acid Sequence; Amino acids; b-Hydroxybutyric acid; b-Ketothiolase; Bacteria; Base Sequence; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biosynthesis; Biotechnology; Blotting, Southern; Burkholderia; Burkholderia - enzymology; Burkholderia - genetics; Burkholderia - growth & development; Deoxyribonucleic acid; DNA; Energy sources; Fractionation; Fundamental and applied biological sciences. Psychology; Genes; Genes, Bacterial; Genetics; Hydroxybutyric acid; Microbiology; Mission oriented research; Molecular Sequence Data; PHA synthase; Polyesters; Polyesters - chemistry; Polyesters - metabolism; Polyhydroxyalkanoates; polyhydroxyalkanoic acid; Restriction Mapping; Sequence Analysis, DNA
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s002530051641

Burkholderia sp. accumulates polyhydrox-yalkanoates (PHAs) containing 3-hydroxybutyrate and 3-hydroxy-4-pentenoic acid when grown on mineral media under limited phosphate or nitrogen, and using sucrose or gluconate as a carbon and energy source. Solvent fractionation and NMR spectroscopic characterization of these polyesters revealed the simultaneous accumulation of two homopolyesters rather than a co-polyester with random sequence distribution of the monomers [Valentin HE, Berger PA, Gruys KJ, Rodrigues MFA, Steinbuchel A, Tran M, Asrar J (1999) Macromolecules 32: 7389-7395]. To understand the genetic requirements for such unusual polyester accumulation, we probed total genomic DNA from Burkholderia sp. by Southern hybridization experiments using phaC-specific probes. These experiments indicated the presence of more than one PHA synthase gene within the genome of Burkholderia sp. However, when total genomic DNA from Burkholderia sp. was used to complement a PHA-negative mutant of Ralstonia eutropha for PHA accumulation, only one PHA synthase gene was obtained resembling the R. eutropha type of PHA synthases, based on amino acid sequence similarity. In addition to the PHA synthase gene, based on high sequence homology, genes encoding a beta-ketothiolase and acetoacetyl-CoA reductase were identified in a gene cluster with the PHA synthase gene. The arrangement of the three genes is quite similar to the R. eutropha poly-beta-hydroxybutyrate biosynthesis operon.