Production of cyclodextrin glucanotransferase (CGTase) from Bacillus G1, a new bacterial isolate was optimized in shake-flask cultures using statistical design approach. An efficient fermentation medium producing CGTase with high activity (54.9 U/ml) was determined. A 2(5) Central Composite Design (CCD; half fraction) has been chosen to elucidate the combined effect of five process variables; tapioca starch, peptone, yeast extract, magnesium sulphate and potassium phosphate concentration. Concentrations of 4% tapioca starch, 2% peptone, 0.04% magnesium sulphate and 1% sodium carbonate have been shown to be optimum for the production of CGTase. (C) 2004 Elsevier Ltd. All rights reserved.