Abstract:Using α-cyclodextrin glycosyltransferase （α-CGTase）as a catalyst，the enzymatic production process of potato starch to produce α-cyclodextrin was studied.The response surface test was designed by single factor test and box-behnken center combination design method to analyze the influence of different conditions on the α-cyclodextrin conversion rate.The experimental results showed that when the reaction temperature of α-CGTase was 50℃ and the pH value was 5.5，α-CGTase exhibited the best enzyme activity，and the conversion rate of α-cyclodextrin was the highest.In the reaction system，the organic solvent n-decanol was added，the substrate concentration was 1.0%，the enzyme amount was 200 U/g starch，and the reaction time was 14 h.The conversion rate of α -cyclodextrin could reach 40.6%.The α -cyclodextrin product was further separated and purified by steam distillation.After identification and analysis by high performance liquid chromatography（HPLC），the conversion rate could reach 20%-40%and the purity could reach 75%.