title: Biosynthesis and characterization of deuterated polyhydroxyoctanoate.
abstract: The synthesis of a polyhydroxyalkanoate with medium chain length alkyl substituents by Pseudomonas oleovoranswas investigated using protonated and deuterated forms of octanoic acid in a minimal salts medium. Cultivation with deuterated octanoic acid resulted in a reduced rate of polymer accumulation compared to that with its protonated counterpart (107 and 207 mg of polymer L(-1) of medium h(-1) of cultivation, respectively). Nuclear magnetic resonance and gas chromatography coupled mass spectrometry of the derivatized polymer was used to establish the extent and distribution of deuterium in the biopolymer. A partially deuterated heteropolymer with 3-hydroxyoctanoic acid as the main constituent was produced. Deuteration is an important tool for contrast variation studies using neutron scattering, but predicates that the deuterated polymer is otherwise comparable in its physiochemical and material properties to its protonated counterpart. In studies reported here, the deuterated biopolymer exhibited an additional diffraction maximum at 7.55 A and slight differences in its melting point (60 and 55 degrees C) and glass transition temperature (-39 and -36 degrees C) when compared to its protonated equivalent. While significant differences between the protonated and deuterated biopolymers were determined, our results support the use of this deuterated polyhydroxyalkanoate in its application in investigations using analytical neutron scattering techniques.
authors.affiliation: Bio/polymers Research Group and Centre for Advanced Macromolecular Design, School of Biotechnology & Biomolecular Sciences, and Nuclear Magnetic Resonance Facility, University of New South Wales, Sydney, NSW 2052, Australia. J.Foster@unsw.edu.au
authors.forename: L John R
authors.initials: LJ
authors.lastname: Foster
authors.forename: Robert A
authors.initials: RA
authors.lastname: Russell
authors.forename: Vorapat
authors.initials: V
authors.lastname: Sanguanchaipaiwong
authors.forename: David J M
authors.initials: DJ
authors.lastname: Stone
authors.forename: James M
authors.initials: JM
authors.lastname: Hook
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Holden
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D011091:Polyesters / Q000737:chemistry* / Q000378:metabolism*; D044204:Pseudomonas oleovorans / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C088151:poly(3-hydroxyoctanoic acid)