Flexible feeding strategy for high-yield PHA bioprocessing in Cupriavidus necator H16 from anaerobically fermented industrial wastewater
Natalia Hernández‐Herreros, Alberto Rodríguez, Virginia Rivero‐Buceta, Antonia Rojas, M. Auxiliadora Prieto
Abstract
Polyhydroxyalkanoates (PHAs) are promising bioplastics. Their cost-effective production might be possible through waste valorisation. This study explores agro-industrial wastewater converted into organic acids by anaerobic acidification as a substrate for PHA biosynthesis by Cupriavidus necator H16. A tailored fed-batch strategy mitigated organic acids toxicity by aligning feed timing with biomass growth and carbon source uptake. This approach enabled PHA accumulation with a final biomass of 19 g/L and 85 % polymer content. This is the highest level of polymer production reported for wild-type C. necator on such complex substrates. The operational mode significantly influenced the properties of the polymer, reducing the polydispersity index from 5.6 to 2.2 and increasing the molecular weight from 3.6 to 5.6 kDa, enhancing the polymer's thermal performance with a melting point of 176 °C. These findings emphasise the importance of feeding strategies in both bioprocess efficiency and PHA properties, providing valuable insights for the production of bioplastics on an industrial scale.