Effect of the reaction temperature on the transglycosylation reactions catalyzed by the cyclodextrin glucanotransferase from Bacillus macerans for the synthesis of large-ring cyclodextrins

摘要

The synthesis of cyclodextrins with from 6 to more than 50 glucose units by cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) from Bacillus macerans was investigated. Analysis of the synthesized cyclic alpha-1,4-glucan products showed that a higher yield of large-ring cyclodextrins were obtained with a reaction temperature of 60 degreesC compared to 40 degreesC. The yield of large-ring cyclodextrins obtained at 60 degreesC represented about 50% of the total glucans employed in the reaction. Analysis of the cyclodextrin-forming cyclization reaction and of the coupling reaction of the CGTase resulting in the degradation of mainly the larger cyclic alpha-1,4-glucans indicated higher rates of the cyclization reaction at 60 degreesC compared to 40 degreesC while the opposite was found for the coupling reaction. (C) 2003 Elsevier Ltd. All rights reserved. [References: 33]