Acid whey permeate: An alternative growth medium for microalgae Tetradesmus obliquus and production of β-galactosidase

Acid whey permeate represents an important disposal problem of the dairy industry and requires simple and economical solutions. This work investigates its use for the production of microalgal biomass and beta-galactosidase enzyme as a value-added product. Results show that biomass and enzyme production increase following the amount of whey permeate used in the medium formulation, but not in a linear fashion. A similar observation was made in regards to mineral salts concentration. Biomass concentrations up to 5 g L-1 were obtained and volumetric enzyme activities up to 400 U L-1. Under best nutrient utilization conditions, shake-flasks and photobioreactor experiments show optimal productivities of 14.60 U L-1 d(-1) and 16.26 U L-1 d(-1) respectively, after 5 and 7 days of culture. Overall results suggest a promising avenue for the utilization of acid whey permeate as a resource for producing useful compounds from microalgae.