Maintenance energy-driven polyhydroxyalkanoates production from food waste digestate by Haloferax mediterranei

This study investigated the role of maintenance energy expenditure in driving polyhydroxyalkanoate (PHA) production from food waste digestate using Haloferax mediterranei. A theoretical model was developed to describe the inhibitory effects on cellular PHA content based on substrate allocation on maintenance energy. This model offered a generalized understanding of the positive correlations between inhibitory effects and corresponding PHA production. For the first time, a method was proposed and experimentally validated to quantify the extent of inhibition, providing an approach to assessing these inhibitory effects. Furthermore, the minimum inhibitory conditions necessary for H. mediterranei to achieve maximum PHA production without excessively compromising cell biomass growth were identified. These findings not only elucidate the intrinsic relationship between maintenance energy expenditure and PHA production but also establish a novel framework for leveraging inhibitory effects, such as those from food waste digestate, to promote sustainable and cost-effective bioplastic production, thereby contributing to circular economy.