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Abstract

INTRODUCTION:Cyclodextrin glycosyl transferase (EC 2.4.1.9) is a unique enzyme capable of converting starch and related substrates into cyclomaltodextrins (CDs) 1 . CDs are cyclic oligosaccharides consisting of α-1, 4-linked 6, 7, or 8-glucopyranose units, usually referred to as α, β, or γ-CDs respectively.CDs possess a unique torus shape and the polar hydroxyl groups are oriented toward the outside, keeping the interior cavity relatively hydrophobic.Therefore, CDs are soluble in water and the hydrophobic environment of the cavity enables them to form inclusion complexes with many organic and inorganic molecules, thereby changing the physical and chemical properties of the included compounds. This is the basis of broad applications in the agriculture, textile, food, cosmetic, and pharmaceutical industries as well as in bioconversions and separation processes 2, 3, 4 .There are several known alkaliphilic Bacillus sp. that are able to produce CGTase.ABSTRACT: 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 MgSO 4 .7H 2 O, K 2 HPO 4 and Na 2 CO 3 . A 3 3 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. QUICK RESPONSE CODE