Poly(3-hydroxyalkanoate)s produced by Pseudomonas oleovorans grown by feeding nonanoic and 10-undecenoic acids in sequence

Abstract

Pseudonwmis oleovorans was grown on nonanoic acid and 10-undecenoic acid, which were fed in sequence. The poly(3-hydroxyalkanoate)s (PHAs) which were isolated from cells harvested at different growth times, were characterized by solvent fractionation, crosslinking ability, gel permeation chromatography, 1H NMR spectroscopy, and differential scanning calorimetry. Two glass transitions were observed for the PHAs produced, and these corresponded to those of the PHAs produced from nonanoic acid [PHA(NA)] and 10-undecenoic acid [PHA(UA)] alone. The amounts of PHAs with repeating units produced from nonanoic acid remained constant while Pseudomonas oleovorans utilized UA for growth and PHA production. The molecular weight distributions of the PHAs obtained at different growth times were also constant. A crosslinking study showed that these polymers were mainly physical mixtures of PHA(NA) and PHA(UA). However, a fractionation study indicated that small amounts of the PHAs contained repeating units from both substrates, PHA(NA/UA).