Physiological characterization and genetic engineering of Pseudomonas corrugata for medium-chain-length polyhydroxyalkanoates synthesis from triacylglycerols.

Pseudomonas belonging to the rRNA-DNA homology group I produce medium-chain-length (mcl)-polyhydroxyalkanoates (PHA). We show that P. corrugata, a member of this group, accumulates 0.5-1.0 g of mcl-PHA/L of culture when grown on glucose (Gl) or oleic acid (Ol). The predominant monomers of Gl-PHA and Ol-PHA are beta-hydroxydecanoate and beta-hydroxyoctanoate, respectively. The molecular masses and polydispersity of P. corrugata PHAs are higher than those typically found with other Pseudomonas. We electrotransformed P. corrugata with a plasmid pCN51lip-1 carrying Pseudomonas lipase genes to generate strain III111-1. The recombinant strain grew on intact triacylglycerols (TAGs) to 1.9-2.7 g of cell-dry-weight/L of culture. The yields and the predominant repeat-units of PHAs obtained from the lard- and tallow-grown III111-1 were similar to those of Ol-PHA from wild-type cells. In contrast to other Pseudomonas species, P. corrugata III111-1 grown on TAGs at temperatures up to 36 degrees C was not significantly affected with regard to cell yields, amounts of PHA produced, and the repeat unit compositions of the polymer.