Long-chain fatty acids as sole carbon source in polyhydroxyalkanoates production by Cupriavidus necator H16

Abstract

Polyhydroxyalkanoates (PHA) are promising eco-friendly alternatives to petrochemical plastics. This study investigated the impact of the main fatty acids present in waste and fresh oils -palmitic, stearic, oleic, and linoleic acid-on PHA production using Cupriavidus necator H16, focusing on production yield, polymer composition, thermal properties, and microbial viability. Experiments were conducted with low (5 g/L) and high (15 g/L) carbon content for 168 h. Oleic acid was the most effective carbon source, yielding higher PHA production rates, especially noticeable at higher concentrations. The monomer composition and thermal properties of PHAs varied with the type and concentration of fatty acid used. Stearic acid produced PHAs with more 3-hydroxyvalerate and medium-chain length monomers. Microbial viability was consistent across all conditions, except for linoleic acid, which had a detrimental effect. These findings provide key insights into optimizing fatty acid selection to enhance PHA production and tailor polymer properties for industrial applications.

Keywords: Bioprocess kinetics; Carbon source; Microbial polymer; Vegetable oil.