Tailoring PHA copolymer types via amino acid supplementation in dairy byproduct media

Abstract

The microbial biotransformation of low-cost feedstock to generate biodegradable biopolymers, as an alternative to synthetic plastics, is a promising strategy for sustainable development. The study investigated the biotransformation of dairy byproduct (whey) into polyhydroxyalkanoate (PHA) copolymers with the supplementation of amino acids using Ralstonia eutropha. The sulphur-containing (cystine, cysteine, methionine) and aromatic (phenylalanine, tryptophan, and tyrosine) amino acids were supplemented. The highest yield of 37.1195% was obtained with tryptophan supplementation. The characterisation of PHA and its copolymers was conducted using ESI–MS and FTIR. This study demonstrates that dairy byproducts can potentially serve as a cost-effective feedstock for producing high concentrations of biopolymers with amino acid supplementation, thereby promoting a sustainable waste management system. © The Author(s) 2025.