Magnesium affects poly(3-hydroxybutyrate-co-4-hydroxybutyrate) content and composition by affecting glucose uptake in Delftia acidovorans

ABSTRACT

Precise control of polyhydroxyalkanoate (PHA) composition is necessary in order to synthesize polymers with specific properties. Among the various types of PHA that have been identified, those that contain 4-hydroxybutyrate (4HB) monomers are especially useful in the medical and pharmaceutical fields as absorbable biomaterial. In this study, we have investigated the effect of magnesium concentration on the biosynthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] by Delftia acidovorans DS-17. Our results show that, magnesium affects the copolymer content and composition by affecting glucose uptake from the culture medium. Higher concentrations of magnesium resulted in lower molar fractions of 3HB in the copolymer and reduced uptake of glucose. The results show for the first time that magnesium may be used to achieve fine control of biologically synthesized PHA copolymer composition