Fermentation of whey and starch by transformed Saccharomyces cerevisiae cells.

Among the main agro-industrial wastes, whey and starch are of prime importance. In previous work we showed that strains of Saccharomyces cerevisiae transformed with the episomal plasmid pM1 allow production of yeast biomass and ethanol from whey/lactose. Ethanol production from whey and derivatives has been improved in computer-controlled bioreactors, while fermentation studies showed that the composition of the medium greatly modulates the productivity (g ethanol produced/l in 1 h of fermentation). A yeast strain for the simultaneous utilization of lactose and starch has also been developed. Biotechnological perspectives are discussed.