CYCLODEXTRIN GLYCOSYLTRANSFERASE PRODUCTION BY ALKALIPHILIC BACILLUS SP. ISOLATED FROM RICE CULTIVATED SOIL AND MEDIA OPTIMIZATION USING TAGUCHI METHOD

A Cyclodextrin glycosyltransferase (CGTase) producer was isolated from soil obtained from rice fields using alkaline Horikoshi II medium. The alkaliphile was characterized microscopically, biochemically and confirmed by 16S rRNA analysis as Bacillus oshimensis. CGTase production is dependent on the strain, medium composition and culture conditions; hence media optimization studies were carried out in shake flask using the statistical method. Tapioca starch was used as carbon source and a combination of yeast extract and peptone were used as nitrogen source in the media, along with MgSO₄.7H₂O, K₂HPO₄ and Na₂CO₃. A 3³ factorial design using Taguchi method has been chosen to elucidate the combined effect of these variables. The parameters were optimized by changing three independent variables, with fixed concentration of mineral sources. The optimal media composition for CGTase production was found to be comprised of Tapioca starch 1%; peptone 0.5%; yeast extract 0.5% and 0.14% Magnesium Sulphate, 0.2% ammonium dihydrogen phosphate according to the factorial designing of the experiment and was used for further studies. The CGTase activity was found to be 4.5 U/ml after media optimization.