Productivity increment of biodegradable and biorenewable copolymer containing 3-hydroxyvalerate monomer initiated by alcohols as precursor substrates

Abstract

Background The production cost and the material properties of polyhydroxyalkanoate (PHA), a biodegradable plastic are common issues of debate. It has become a constant challenge for researchers to find suitable and relatively cheap carbon substrates. This study has investigated the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)], using a combination of fatty acids and alcohols. The fermentation process described in this study also highlights the potential use of 1-pentanol for the generation of 3HV monomer, in contrast to odd carbon numbered volatile fatty acids, which are known to exert some levels of toxicity towards the cells. Results Among the various mixtures of fatty acids and 3HV precursors, the mixture of 0.50 wt% C oleic acid and 0.06 wt% C 1-pentanol was found suitable for the production of this copolymer. It was found that Cupriavidus sp. USMAA2-4 could produce up to 56 wt% of P(3HB-co-3HV) with 8 mol% 3HV monomer units. The 3HV monomer composition was also successfully regulated in the range 3–66 mol% by manipulating the culture conditions. The number average molecular weight of the copolymer produced was in the range 217–351 kDa. Conclusion The findings of this study might be used as a platform for scale-up production of 3HV copolymers with different monomer compositions using mixtures of oleic acid and alcohols, namely 1-pentanol for a sustainable production process.© 2012 Society of Chemical Industry