Production of Cyclodextrins from Unliquefied Constarch Using Cyclodextrin Glycosyltransferase in a Membrane Bioreactor
Tae-Jong Kim, Yun-Dong Lee, and Hak-Sung Kim
Cyclodextrins are cyclic and doughnut shaped with an interior cavity whose size and shape are determined by the number if glucose units. The interior of cyclodextrin is relatively apolar compared to water, and thereby cyclodextrins have a specific function of forming an inclusion complex with many organic substances. The application of cyclodextrins has been rapidly increasing in the food, cosmetic,pharmaceutical, agrochemical, and plastics industries as emulsifiers, antioxidants, and stabilizing agents.In our previous paper, cyclodextrins were effciently produced from unliquefied corn starch without by-product in an attrition bioreactor in which hydrolysis of starch and synthesis of cyclodextrins by cyclodextrin glycosiltransferase(CGTase) occur simultaneously.We have been investigating various approaches to increase the production yield of cyclodextrins from unliquefied corn starch. It was found that CGTase is severely inhibited by cyclodextrins. The relative activity of CGTase decreased to 50% in the presence of 6.0g/L -cyclodextrin. Based on the above observation, a membrane bioreactor system was employed to increase the production yield of cyclodextrins by reducing product inhibition.