Enzyme having a degrading ability for dextran microorganism producing same preparation methods and composition containing same

摘要

PURPOSE: Provided is an enzyme produced by a microorganism which decomposes dextran and starch, present in the raw sugar of sugar cane and sugar beet, to simplify the sugar making process and enhance the quality of sugar by reducing the content of dextran in the final sugar product. CONSTITUTION: The preparation method comprises: a step of culturing Lypomyces starkeyi(ATCC 74054); a step of treating the cultured Lypomyces starkeyi ATCC 74054with ethylmethane sulfonate; a step of spraying the above treated microorganism and culturing on a plate containing starch, 2-dioxy-D-glucose, blue dextran and agar; and a step of selecting dextranase and amylase with excellent activity by the degree of transparency in dextran circle and iodine experiment to obtain Lypomyces starkeyi KDM1(KCTC 10026BP). The DXAMase recovered from the above precess has molecular weight of 100kDa and possesses the activity of dextranase and amylase simultaneously.The decomposition method of dextran consists of adding 0.1-1 unit/ml of above DXAMase and treating for 10-15 minutes at 30-60deg.C and at pH5.5-6.5 initial juice,concentrated syrup or massecuite of sugar cane or sugar beet wherein 3-5% of each starch and dextran and 40-60% of sugar are contained.