LAUSR

&NA; Cost‐effective consolidated bioprocessing (CBP) of raw starch for biofuel production requires recombinant Saccharomyces cerevisiae strains expressing &agr;‐amylases and glucoamylases. Native Aureobasidium pullulans apuA, Aspergillus terreus ateA, Cryptococcus sp. S‐2 cryA and Saccharomycopsis fibuligera sfiA genes encoding raw‐starch &agr;‐amylases were cloned and expressed in the S. cerevisiae Y294 laboratory strain. Recombinant S. cerevisiae Y294[ApuA] and Y294[AteA] strains produced the highest extracellular &agr;‐amylase activities (2.17 U mL‐1 and 2.98 U mL‐1, respectively). Both the ApuA and AteA &agr;‐amylases displayed a preference for pH 4 to 5 and retained more than 75% activity after 5 days at 30°C. When ateA was co‐expressed with the previously reported Aspergillus. tubingensis glucoamylase gene (glaA), the amylolytic S. cerevisiae Y294[AteA‐GlaA] strain produced 45.77 g L‐1 ethanol after 6 days. Ethanol production by this strain was improved with the addition of either 2.83 &mgr;L STARGEN 002 (54.54 g L‐1 ethanol and 70.44% carbon conversion) or 20 &mgr;L commercial glucoamylase from Sigma‐Aldrich (73.80 g L‐1 ethanol and 90.19% carbon conversion). This is the first report of an engineered yeast strain that can replace up to 90% of the enzymes required for raw starch hydrolysis, and thus contributes to the realisation of a CBP yeast for starch‐based biofuel production.