Optimization of polyhydroxyalkanoate (PHA) production from biohythane pilot plant effluent by Cupriavidus necator TISTR 1335

Bioplastics, particularly polyhydroxyalkanoates (PHAs), are emerging as promising alternatives to traditional materials due to their biodegradability. This study focuses on the production of PHAs as bioplastics using effluent from hydrogen production in a two-stage Biohythane Pilot Plant, which provides a low-cost substrate. The aim is to optimize production conditions, with Cupriavidus necator TISTR 1335 being used as the PHA producer. Utilizing Response Surface Methodology-Central Composite Design, we explored optimal conditions, revealing peak PHA production at a substrate concentration of 33.51 g COD/L and a pH of 6.87. The predicted optimal PHA concentration was at 3.05 g/L within the established model, closely matching the experimentally validated value of 3.02 g/L, with the overall usage rate of reducing sugars approximately 50–60%. This study underscores the importance of optimizing PHA production conditions and paving the way toward large-scale PHA production.