A simple and specific recovery method for alpha-cyclodextrin (alpha-CD) was developed by employing co-digestion of CD reaction mixtures with CGTase from Bacillus ohbensis and alpha-glucosidase. The combination of CGTase from B. ohbensis and alpha-glucosidase, such as alpha-amylase, beta-amylase, or glucoamylase was examined for the selective degradation of beta- gamma-CD in the CD reaction mixture formed by CGTase from B. macerans. The co-digestion of the CD mixture with Taka-amylase and the CGTase resulted in alpha-CD and maltodextrins, the combination with beta-amylase resulted in alpha-CD and maltose, and that with glucoamylase resulted in alpha-CD and glucose. The conditions of selective degradation of beta- and gamma-CD by co-digestion with the CGTase and glucoamylase were optimized as follows : the incubation pH, 5.5; incubation temperature, 50 degrees C; CGTase concentration, 15 u/g of substrate; glucoamylase, 10 u/g of substrate; substrate concentration, 10% (w/v); the incubation time was fixed for 18 hr from the stand point of operation convenience.