RESUMO
Medium-chain-length (mcl)-polyhydroxyalkanoates (PHAs), elastomeric polyesters synthesized by Genus Pseudomonas bacteria, generally have many different monomer components. In this study, PHAs biosynthesized by four type strains of Pseudomonas (P. putida, P. citronellolis, P. oleovorans, and P. pseudoalcaligenes) and a typical PHA producer (P. putida KT2440) were characterized in terms of the monomer structure and composition by gas chromatography-mass spectrometry (GC-MS) analysis. With a thiomethyl pretreatment of PHA methanolysis derivatives, two unsaturated monomers, 3-hydroxy-5-dodecenoate (3H5DD) and 3-hydroxy-5-tetradecenoate (3H5TD), were identified in mcl-PHAs produced by P. putida and P. citronellolis. The quantitative analysis of PHA monomers was performed by employing GC-MS with methanolysis derivatives, and the results coincided with those obtained by performing nuclear magnetic resonance spectroscopy. Only poly(3-hydroxybutyrate) was detected from the P. oleovorans and P. pseudoalcaligenes type strains. These analytical results would be useful as a reference standard for phenotyping of new PHA-producing bacteria.
