Biosynthesis of Multi-component Polyhydroxyalkanoates by the Bacterium Wautersia Eutropha

Abstract

The study addresses the effect of different conditions of carbon nutrition on synthesis of polyhydroxyalkanoates by the bacterium Wautersia eutropha. In experiments with two wild-type strains (H16 and B5786) it has been first found that under mixotrophic growth conditions – CO2 + co-substrate (alkanoic acids) – bacteria can synthesize multi-component PHAs, consisting of short- and medium-chain-length monomers with carbon chains containing 4 to 8 atoms. It has been shown that PHA composition is determined by the type of the co-substrate. Fatty acids with odd number of carbons induce bacteria to synthesize four- and five-component PHAs with hydroxybutyrate, hydroxyvalerate, and hydroxyhexanoate as major monomers and hydroxyhexanoate and hydroxyoctanoate as minor, occasionally occurring, ones. Fatty acids with even number of carbons induce synthesis of not only their respective monomers (hydroxyhexanoate and hydroxyoctanoate) but also hydroxyvalerate, making possible synthesis of four-component PHAs, containing hydroxybutyrate and hydroxyhexanoate as major components (up to 18 mol%). A family of short- and medium-chain-length four- and five-component PHAs has been synthesized and their physicochemical properties examined.