An investigation into the ability of three fungi and one yeast to grow and capture nutrients in cheese whey

This study addresses the environmental and waste disposal challenges dairy processing poses, namely its most nutrient-rich byproduct – whey. Here, the potential of four fungi/yeast species (Geotrichum candidum, Penicillium corylophilum, Penicillium restrictum, Pleurotus ostreatus) was investigated for nutrient reclamation of whey and production of value-added biomass. Conducted in closed and open batch systems, the study evaluates oxygen uptake rates (OUR), biomass yields, and nutrient removal efficiencies at varying mixing speeds. Results show that pellet formation, pH changes, and biomass nutrient content were species-specific. Among the species, P. corylophilum shows promise with high biomass yields (13.21 g DW L⁻¹, 2.0 g/g COD removed) and nutrient removal efficiencies of 26 % COD, 35 % N-tot, and 41 % P-tot. While further optimisation is needed, P. corylophilum shows potential for bioremediation and improved circularity in the dairy industry. Efficacy could be enhanced through bioreactor optimisation, such as employing a continuously fed bubble reactor.