Mixed Culture PHA Production With Alternating Feedstocks: Process Robustness And Population Dynamics

Polyhydroxyalkanoates (PHA) are a sustainable alternative to conventional plastics that can be obtained from industrial wastes/by-products using mixed microbial cultures (MMC). MMC PHA production is commonly carried out in a 3-stage process consisting of an acidogenic stage, a PHA producing culture selection stage, and a PHA production phase. This work investigated the performance robustness and microbial population dynamics of a PHA producing MMC when subjected to a feedstock shift, mimicking a seasonal feedstock scenario, from cheese whey to sugar cane molasses. Research was focused on the possibility of tailoring PHA through the selection of feedstock: either using feedstocks with different compositions or mixing two or more fermented substrates with different organic acid profiles. This knowledge is expected to contribute to the extended application of this promising process for resource recovery from industrial wastes.