C-13 NMR-SPECTROSCOPY IN LIVING CELLS OF PSEUDOMONAS-OLEOVORANS

Natural abundance solution C-13 nuclear magnetic resonance (n.m.r.) sp ectroscopy was used to monitor the intracellular production and degrad ation in vivo of two poly(3-hydroxyalkanoates) (PHAs), produced by Pse udomonas oleovorans, poly(3-hydroxynonanoate), (PHN), poly(3-hydroxyph enylvalerate) (PHPV) and a blend of both Pi-IN and PHPV. PHN was produ ced and degraded faster than PHPV when it was either the sole intracel lular polyester or a component of a blend with PHPV. However, the rate of PHPV degradation was increased dramatically when PHN was present. Comparison of the n.m.r. method for quantitative monitoring of the PHA s with that of extracting and weighing the polymers from freeze-dried cells, showed that the C-13 n.m.r. method was faster, easier, non-dest ructive (to the cells) and more accurate, while giving additional valu able information on the mobility and the composition of the PHAs prese nt. This method was also particularly useful for determining optimal h arvest times because PHPV formation continued long after the maximum o ptical density was reached. (C) 1997 Elsevier Science Ltd.