Utilization of lactose and whey permeate for the sustainable production of polyhydroxyalkanoates by Hydrogenophaga pseudoflava DSM1034

The utilization of agri-food wastes holds significant importance from both environmental and economic standpoints. Whey permeate, a by-product of cheese manufacturing with high lactose content, could be considered a promising substrate for microbial growth to yield value-added products. Whey permeate was therefore investigated as a potential feedstock for the production of polyhydroxyalkanoates (PHAs) by Hydrogenophaga pseudoflava DSM1034. Although the ability of this microorganism to grow and accumulate PHAs on whey permeate has been previously demonstrated, the PHAs yields were notably low. Therefore, a meticulous inoculum optimization was performed, taking into consideration adaptation to lactose-containing substrates, initial bacterial concentration, and growth kinetics. In media containing lactose as a carbon source, the lag phase, exceeding 40 hours in non-optimized conditions, decreased to only 4 hours. In whey permeate, a cell dry weight (CDW) of 5.49 ± 0.08 g/L was obtained. P...