Synthesis of P(3HB‐co‐3HHx) copolymers containing high molar fraction of 3‐hydroxyhexanoate monomer by Cupriavidus eutrophus B10646

BACKGROUND: P(3HB‐co‐3HHx) copolymers are very promising biomaterials. The main challenge in the production of these polymers is to simultaneously achieve high cell biomass; high P(3HB‐co‐3HHx) content; and high molar fraction of 3HHx in P(3HB‐co‐3HHx). The most common approach to production of these copolymers is the use of recombinant bacterial strains. The purpose of this study was to optimize the process of production of P(3HB‐co‐3HHx) copolymers containing high molar fractions of 3HHx by using the wild‐type strain Cupriavidus eutrophus B10646. RESULTS: Kinetic properties of C. eutrophus B10646 were studied during cultivation of the cells on substrates necessary for P(3HB‐co‐3HHx) synthesis: glucose, nitrogen, sodium hexanoate, and sodium acrylate. The physiological ranges of their effects were determined experimentally, and C. eutrophus B10646 was grown in culture media with different dosages of these substrates. P(3HB‐co‐3HHx) copolymers with different molar fractions of 3HHx, including high ones (12 to 68%), were synthesized, and their physicochemical and mechanical properties were investigated. CONCLUSION: For the first time, cultivation conditions of Cupriavidus eutrophus B10646 enabled production of high biomass yields (5–6 g L‐¹) and high content of the polymer (60–75%) that contained high 3HHx molar fraction. By varying the 3HB/3HHx ratio, one can change physicochemical and mechanical properties of P(3HB‐co‐3HHx) copolymers. © 2014 Society of Chemical Industry