Production of polyhydroxyalkanoic acids by Ralstonia eutropha and Pseudomonas oleovorans from an oil remaining from biotechnological rhamnose production

Screening experiments identified several bacteria which were able to use re sidual oil from biotechnological rhamnose production as a carbon source for growth. Ralstonia eutropha H16 and Pseudomonas oleovorans were able to use this waste material as the sole carbon source for growth and for the accum ulation of polyhydroxyalkanoic acids (PHA). R. eutropha and P. oleovorans a ccumulated PHA amounting to 41.3% and 38.9%, respectively, of the cell dry mass, when these strains were cultivated in mineral salt medium with the oi l from the rhamnose production as the sole carbon source. The accumulated P HA isolated from R. eutropha consisted of only 3-hydroxybutyric acid, where as the PHA isolated from P. oleovorans consisted of 3-hydroxydroxyhexanoic acid, 3-hydroxyoctanoic acid, 3-hydroxydecanoic acid, and 3-hydroxydodecano ic acid. The composition was confirmed by gas chromatography of the isolate d polyesters. Batch and fed-batch cultivations in stirred-tank reactors wer e done.