Potential of the lactate-driven polyhydroxyalkanoates (PHA) production via mixed microbial culture

The study investigates polyhydroxyalkanoates (PHA) production from lactic acid-rich substrates via mixed microbial cultures (MMC) using lactic acid rather than traditional volatile fatty acids (VFAs) as precursors. A MMC capable of producing PHA directly from a synthetic lactic acid solution was selected through the feast and famine approach by applying an organic loading rate (OLR) of 1.2 gC L-1 and an uncoupled strategy for nutrient feeding. Preliminary accumulation tests showed that the selected biomass was able to reach up to 50% of PHAs accumulation by dry weight, primarily as hydroxybutyrate (HB). These findings underscore the potential of using lactic acid, potentially derived from dark fermentation of lactose-containing agro-industrial residues like cheese whey, for cost-effective and sustainable PHA production