Rapid affinity purification processes for cyclodextrin glycosyltransferase from Bacillus circulans

Two rapid and easy-to-scale-up methods for the purification of cyclodextrin glycosyltransferase (CGTase) from Bacillus circulans were developed: affinity precipitation with starch and aqueous two-phase partition. The first method, optimised by a factorial design, gave an 80% CGTase adsorption at 11% starch and 1.6% ammonium sulphate, and a 65% recovery after elution with 10 mM alpha-cyclodextrin. The purification factor was 17. Aqueous two-phase partition yielded a 72% CGTase recovery in a two-step procedure; CGTase was obtained in the bottom phase with a purification factor of 37.