Evaluation of starch fermentation products by amylolytic recombinant Saccharomyces cerevisiae strains

Starch fermentation products were obtained with two amylolytic recombinant Saccharomyces cerevisiae strains (MFLA2 and MFLB5). MFLA2 secretes the Aspergillus awamori glucoamylase and the Bacillus subtilis a-amylase. MFLB5 secretes the same amylolytic enzymes but as a bifunctional fusion protein. Starch consumption, biomass growth, ethanol production, fermentation efficiency and ethanol yields referring to consumed substrate and biomass are discussed. Both recombinant strains showed similar ethanol production levels when glucose was replaced by soluble starch as the sole carbon source.