Delftia acidovorax DSM 39 engineered to produce polyhydroxyalkanoates from fatty-waste material.

The aim of this work was to find bacterial strains able to utilize, as carbon source, low cost industrial lipid wastes such as triacylglycerols (TAGs) from vegetable oils and animal fats, with the final objective to produce polyhydroxyalkanoates (PHAs). PHAs are energy/carbon storage materials accumulated by a number of bacterial species under stress growth conditions and excess of carbon availability. A variety of different polyhydroxyalkanoates can be synthesized and accumulated in the cytoplasm by prokaryotes as insoluble inclusions. Delftia acidovorans has been studied for its ability to produce medium chain-length polyhydroxyalkanoates and because it is known to efficiently accumulate PHA containing high molar fractions of 4-hydroxybutyrate (4HB). The presence of 4HB units into PHA samples confers to the polymer greater flexibility Unfortunatelly D. acidovorans is unable to metabolize triacylglycerols like fat, oil and grease, For these reasons, the collection strain D. acidovorans DSM39 was genetically modified and used as a recipient of genes required for lipid degradation. From a recent soil isolation program, several bacterial strains were found to possess remarkable lipolytic activities. Among these isolates, Pseudomonas stutzeri BT3 was selected as a potential donor of lipolytic genes that were identified and sequenced. A recombinant plasmid, pBBR1MCS-5, carrying P. stutzeri BT3 lipase genes (lipC and lipH) was used to transform D. acidovorans DSM39. The obtained recombinant strains showed interesting TAG-hydrolysing activity as determined by rhodamine B fluorescence plate assay