Production of poly-(β-hydroxybutyrate) from saponified Vernonia galamensis oil by Alcaligenes eutrophus

Saponified vernonia oil was converted exclusively to poly(beta-hydroxybutyrate) (PHB) by Alcaligenes eutrophus in a single-stage batch culture. After harvesting, centrifugation followed by lyophilization, the resulting dried cells contained up to 42.8 wt% PHB having a peak molecular mass of 381863 Da, weight-average molecular mass of 308390 Da, and a polydispersity of 1.1, The PHB had a melting point (T-m) range of 163-174 degrees C with a maximum at 172 degrees C (lit. T-m, 175 degrees C), and heat of fusion of 18.43 cal g(-1). Fermentation performed under varying conditions of nitrogen limitation indicated that there was no significant effect of nitrogen concentration on the molecular mass of PHB produced from vernonia oil by A. eutrophus.