METABOLIC ANALYSIS OF SACCHAROMYCES-CEREVISIAE STRAINS ENGINEERED FORMALOLACTIC FERMENTATION

A complete malolactic fermentation was achieved using Saccharomyces ce revisiae strains coexpressing the genes mleS and mae1 coding for the L actococcus lactis malolactic enzyme and the Schizosaccharomyces pombe malate permease under the control of yeast promoters. The expression l evel of mae1 greatly influences the kinetics of the reaction by contro lling the rate of malate uptake meanwhile a high expression level of m leS induces a partial consumption of malate derived from glucose by th e malolactic enzyme. A strain expressing several copies of mae1 and on e copy of mleS degrades 3 g/l of malate almost exclusively through the malolactic pathway in 4 days under enological conditions, without met abolic side effects. (C) 1997 Federation of European Biochemical Socie ties.