Valorization of waste glycerol for the production of poly (3-hydroxybutyrate) and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer by Cupriavidus necator and extraction in a sustainable manner.

Glycerol is a by-product of many industrial processes and huge amounts of it are generated in the form of waste, thereby necessitating a search for the method of its disposal. An interesting solution is the valorization of crude glycerol into value added product such as polyhydroxyalkanoates (PHAs). The feasibility of producing PHAs by Cupriavidus necator was evaluated using crude glycerol (WG). Various cultivation strategies were designed for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer by adding different organic acids as precursors at different concentrations levels. Batch cultivation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production showed accumulation of 6.76g/L biomass containing 4.84g/L copolymer on WG with a maximum 3-hydroxyvalerate content of 24.6mol%. PHAs extraction using a non-toxic and recyclable solvent, 1,2 propylene carbonate, showed the highest recovery yield (90%) and purity (93%) at 120°C temperature and 30min incubation. This is the first report on jatropha based glycerol valorization for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production coupled with extraction using non-toxic solvent.