Discovery and Characterization of a Novel Method for Effective Improvement of Cyclodextrin Yield and Product Specificity

Cyclodextrins(CDs) are widely used in food, pharmaceuticals, drug delivery, and chemical industries and in agriculture and environmental engineering. To improve the yield and selectivity of CDs, this work presented a facile, scalable and efficient enzymatic synthesis of β-CD from starch using β-cyclodextrin glycosyltransferase (CGTase, EC 2.4.1.19) from Bacillus cereus. First, we found that the pretreatment of starch dramatically influenced CDs yield that was related to the structure and molecular weight of the substrate starch. Second, alcohol solvents influenced the yield and product selectivity of CDs; tertiary alcohols enhanced CDs yield(from 54.95% to 68.21%) and secondary alcohols increased the product selectivity(β-CD/γ-CD changed from 6.25 to 8.05). Fluorescence quenching analysis showed that the binding constants and entropy of the solvents influenced the yield and product selectivity, respectively. In conclusion, the results demonstrate that this study provides a promising method for the industrial production of β-CD.