Abstract: Conditions of cyclodextrin glycosyltransferase (CGTase) production by Bacillus alkalophilus12-7 were studied. The optimal fermentation conditions for cyclodextrin glycosyltransferase production were determined by a single-factorial experiment and orthogonal experiment. The results showed that the optimal conditions were as follows: amount of inoculum is 3%; incubation temperature 30℃; pH 10.5. The compositions of fermentation medium were maize powder 2%, yeast extract 1. 5% and corn steep liquor 5%. The load of 250ml-flask was 30ml and the shaking incubation took 3d at 270r/min and the enzyme activity could reach to 5400 U/ml.In 10L-fermentor the enzyme activity could reach as high as 5820U/ml.

Key words: Bacillus alkalophilus, cyclodextrin glycosyltransferase, fermentation conditions optimization