Poly(3-hydroxyalkanoates)

abbreviated as PHAs are a series of bacterial storage polyesters

currently receiving much attention because of their potential application as biodegradable

biocompatible materials.This paper studied the influence of glucose as the carbon source

nitrogen source

and phosphate on the structure of polymer synthesized by DG17

a mutant isolated from oilfield.The structure of polymer was determined by gas chromatograph(GC)

nuclear magnetic resonance(NMR) analysis.Under the experimental conditions

a thermoplastic elastomer P(MO-co-HD) with molecular weight 1.16×105 was synthesized when concentration of ammonium sulfate were not over 1g/L.But thermoplastics PHB was isolated from cells when concentration of ammonium sulfate was up to 8g/L. During these two concentrations

no polymer was found in cells. Concentrations of nitrogen and phosphate maybe have great influence on the pathway of PHA synthesis. 5 was the lowest weight ratio of glucose to ammonium sulfate needed for DG17 to accumulated PHA in cells. Both P(HO-co-HD) and PHB synthesized by DG17 from glucose lost up to 90% weights in activated sludge in one month.