CHARACTERIZATION OF A NEW PSEUDOMONAS ISOLATE, CAPABLE OF ACCUMULATING POLYESTERS OF MEDIUM-CHAIN LENGTH 3-HYDROXYALKANOIC ACIDS

In a screening program for bacterial strains which produce interesting compositions of polyhydroxyalkanoates (PHAs) the strain PHA1 was isol ated displaying an unusual PHA pattern, The presence of ubiquinone wit h nine isoprenoid units in the side chain (Q-9), putrescine and spermi dine as the dominating compounds in the polyamine pattern, the charact eristic fatty acid profile as well as partial 16S rDNA analysis clearl y indicated, that the isolate is a member of the genus Pseudomonas and closely related to Pseudomonas fluorescens. The strain PHA1 and Pseud omonas fluorescens bv. IV DSM 50415 were investigated for PHA accumula tion capabilities. In both strains, alkanoates which corresponded to t he carbon chain length (C6-C10) of the fatty acids added as substrate dominated in the PHA patterns and the carbon chain length was reduced by two C-atoms when undecanoate or dodecanoate was fed. Most of the ot her polymers produced consisted mainly of decanoate or dodecanoate. Wh en the complex medium was supplemented with butyric acid the incorpora tion of 3-OH butyric acid into the polymer was observed. This resulted in the production of PHA blends or possibly even in the production of mixed copolymers with a significant amount of 3-OH butyric acid in ad dition to medium chain length PHAs.