METHOD FOR PRODUCING SUGAR AND PRODUCTION PLANT THEREFOR

摘要

PURPOSE:To produce glucose from starch without necessitating cooling and neutralization steps, by using a novel acid-fast and heat-resistant glucoamylase as saccharase. CONSTITUTION:Starch is liquefied with an alpha-amylase and the produced dextrin is saccharified with a glucoamylase. The liquefaction and saccharification of starch is carried out in acidic state essentially in the absence of metallic ion at >=70 deg.C. The glucoamylase used in the above process is a heat-resistant glucoamylase having high acid resistance and heat-resistance characterized by the optimum working pH of 4-5, half-period of >=3hr at 4.5 pH and 70 deg.C and of >=120hr at 65 deg.C and exhibiting the heat-resistance even in the absence of calcium ion. The alpha-amylase is a heat-resistant alpha-amylase having high acid resistance and heat-resistance characterized by the optimum working pH of 2-5.5 and a half-period of >=80hr at 4.5 pH and 80 deg.C and exhibiting the heat- resistance in the presence of <=10muM of calcium ion.