IDENTIFICATION OF 5-HYDROXYHEXANOIC ACID, 4-HYDROXYHEPTANOIC ACID AND4-HYDROXYOCTANOIC ACID AS NEW CONSTITUENTS OF BACTERIAL POLYHYDROXYALKANOIC ACIDS

A recombinant strain of Pseudomonas putida GPp104 (pHP1014::E146), whi ch expressed tile polyhydroxyalkanoic acid (PHA) synthase of Thiocapsa pfennigii exhibiting an unusual substrate specificity at a high level was incubated in two-stage batch or fed-batch accumulation experiment s with 5-hydroxyhexanoic acid (5HHx) as carbon source in the second cu ltivation phase, copolyesters of 3-hydroxybutyric acid (3HB) plus 5HHx , or of 3HB, 3-hydroxyhexanoic acid (3HHx) plus 5HHx were accumulated as revealed by gas-chromatographic and C-13-NMR spectroscopic analysis . When the recombinant P. putida GPp104 was incubated with 4-hydroxyhe ptanoic acid (4HHp) as carbon source in the second cultivation phase, a copolyester consisting of 3HB, 3-hydroxyvaleric acid and 3- and 4-hy droxyheptanoic acid accumulated. Providing 4-hydroxyoctanoic acid as c arbon source in the second cultivation phase led to the accumulation o f a polyester that contained 1-2 mol% 4-hydroxyoctanoic acid besides 3 -hydroxyoctanoic acid, 3HHx, 3-hydroxyvaleric acid and 3HB. In additio n to PHA containing these new constituents, PHA with 4-hydroxyvaleric acid was accumulated from laevulinic acid. Eleven strains from five ge nera have been also analysed for their ability to utilize different ca rbon sources for colony growth, which might serve as potential precurs ors for the biosynthesis of PHA with unusual constituents. Although mo st of the carbon sources were utilized by some strains for colony grow th, accumulation experiments gave no evidence for the accumulation of new PHA by these wild-type strains.