Biosynthesis and biocompatibility of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) produced by Cupriavidus necator from spent palm oil

The ability of Cupriavidus necator to grow and produce poly(3-hydroxybutyrate-co-4-hydroxybutyrate), P(3HB-co-4HB), on spent palm oil left after frying activities, and 1,4-butanediol as precursors of 3HB and 4HB, respectively, was evaluated. The isolated polymer was characterized by 13C NMR spectroscopy and differential scanning calorimetry. The mole fraction of 4-hydroxybutyrate units was 15 mol% despite the presence of polar compounds like triglyceride trimers in the spent palm oil. The results demonstrate that inexpensive spent palm oil is an excellent carbon source for efficient production of PHA using C. necator. The isolated biopolyester was subjected to a depyrogenation procedure and either blended with vitamin E or physically immobilized on collagen and the biocompatibility of the biopolyester films were evaluated in chick chorioallantoic membrane (CAM). The biocompatibility evaluation indicates that the depyrogenated poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blends have the potential to be developed as a new absorbable biomaterial for medical applications.