The influence of ToruzymeA (R) cyclomaltodextrin glucanotransferase concentration and the presence of ethanol have been studied for the production of alpha-, beta-, and gamma-cyclodextrins (CDs) from 15% (w/v) cornstarch, at 65 A degrees C and pH 6, with the aim of increasing CD yield. The selected concentrations for a single batch reactor were 10% (v/v) ethanol and 0.1% (v/v) enzyme, yielding after 12 h, 37% total CDs, of which 52.2% was alpha-CD, 38.8% beta-CD, and 9.0% gamma-CD. The enzyme specific activities per unit mass of protein for producing alpha-, beta-, and gamma-CD were 37.25, 19.61, and 8.63 U mg(-1), respectively. Total CD yield per milliliter of enzyme was 55 g. To increase CD yield per enzyme charge and thus reduce costs, the production of CDs was tested with two sequential batches in which a single enzyme charge was used. At the end of the first batch, the enzyme was adsorbed either on 65 A degrees C pretreated starch granules or on raw starch, and a second batch was run with this material. The best result, in this case, was obtained for pretreated starch, increasing total CD produced by 57.4%, with 53.2% alpha-CD, 36.1% beta-CD, and 10.7% gamma-CD. CD yield per milliliter of enzyme was then 87 g.