Extractive Bioconversion of Gamma-Cyclodextrin and Recycling of Cyclodextrin Glycosyltransferase in Liquid Biphasic System Using Thermo-Separating Polymer

• Main Authors: Yu Kiat Lin, Pau Loke Show, Yee Jiun Yap, Arbakariya Ariff, Mohamad Suffian Bin Mohamad Annuar, Oi Ming Lai, Tau Chuan Ling, Eng Poh Ng
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2018-10-01
• Series: Frontiers in Chemistry
• Subjects: liquid biphasic system; ethylene oxide-propylene oxide; extractive bioconversion; cyclodextrin; Bacillus cereus
• Online Access: https://www.frontiersin.org/article/10.3389/fchem.2018.00448/full
• ISSN: 2296-2646

An extractive bioconversion conducted on soluble starch with cyclodextrin glycosyltransferase (CGTase) enzyme in ethylene oxide-propylene oxide (EOPO)/potassium phosphates liquid biphasic system (LBS) to extract gamma-cyclodextrin (γ-CD) was examined. A range of EOPO (with potassium phosphates) molecular weights was screen to investigate the effect of the latter on the partioning efficency of CGTase and γ-CD. The results show that the optimal top phase γ-CD yield (74.4%) was reached in 35.0% (w/w) EOPO 970 and 10.0% (w/w) potassium phosphate with 2.0% (w/w) sodium chloride. A theoretical explanation for the effect of NaCl on γ-CD was also presented. After a 2 h bioconversion process, a total of 0.87 mg/mL concentration of γ-CD was produced in the EOPO/ phosphates LBS top phase. After the extraction of top phase from LBS, four continuous repetitive batches were successfully conducted with relative CGTase activity of 1.00, 0.86, 0.45, and 0.40 respectively.