Polyhydroxybutyrate production by Cupriavidus necator in a corn biorefinery concept

The high costs of bioplastics' production may hinder their commercialization. Development of new processes with high yields and in biorefineries can enhance diffusion of these materials. This work evaluated the pro-duction of polyhydroxybutyrate (PHB) from the combination of milled corn starchy fraction hydrolysate and crude glycerol as substrates by the strain Cupriavidus necator LPB 1421. After optimization steps, maximum accumulation of 62 % of PHB was obtained, which represents 11.64 g.L-1 and productivity of 0.162 g.Lh-1. In a stirred tank bioreactor system with 8 L of operational volume, 70 % of PHB accumulation was reported, rep-resenting 14.17 g.L-1 of the biopolymer with 0.197 g.Lh-1 productivity. PHB recovery was conducted using a chemical digestion method, reaching >99 % purity. Therefore, the potential application of milled corn as sub-strate for PHB production was confirmed. The developed bioplastic process could be coupled to a bioethanol producing unit creating the opportunity of a sustainable and economic biorefinery.

Automated summary

The high costs of bioplastics' production may hinder their commercialization. Development of new processes with high yields and in biorefineries can enhance diffusion of these materials. This study evaluated the production of polyhydroxybutyrate (PHB) from corn starchy fraction hydrolysate and crude glycerol by Cupriavidus necator LPB 1421. The optimized process achieved a maximum accumulation of 62% PHB, with a productivity of 0.162 g.Lh-1. The potential application of corn as substrate for PHB production was confirmed, and the developed bioplastic process could be coupled to a bioethanol producing unit creating the opportunity of a sustainable and economic biorefinery.