Purification of α-Cyclodextrin Glycosyltransferase and Study of Thermal Stability Improvement by Chemical Modification

Abstract:

The-cyclodextrin glycosyltransferase(α-CGTase) from Paenibacillus macerans,Escherichia coli,Bacillus subtilis were purified respectively through a combination of ion-exchange and hydrophobic interaction chromatography.Specific activities of the CGTase from these three sources were 201 U/mg,200 U/mg and 199 U/mg,respectively.Chemical modification was further performed to improve the thermal stability of α-CGTase.The α-CGTase expressed in E.coli was cross-linked into a stable macromoleculs by glutaraldehyde.After water bathed at 50 ℃ for 30 min the stability of α-CGTase was improved as the cross-linked α-CGTase exhibit 78% left enzyme activity,which was 3.9 folds higher than that of dissociated α-CGTase.