Cyclic utilization of HP-β-CD in the bioconversion of cortisone acetate by Arthrobacter simplex

Objective: To establish a method for the recovery and reutilization of hydroxypropyl-β-cyclodextrin (HP-β-CD) to lower the cost of its industrial application in cortisone acetate bioconversion.

Results: HP-β-CD is not degraded by Arthrobacter simplex CPCC140451 (ASP) resting cells and 96.4 % HP-β-CD could be recovered by isobutyl acetate extraction. Moreover, the inclusion ability of recovered HP-β-CD barely decreased. The saccharide metabolic and catalytic activities of ASP were greater in the aqueous phase after extracting with isobutyl acetate than other organic solvents. Cyclic utilization tests showed that cortisone acetate conversion ratio was 91.0 % after eight cycles and reached 95.7 % with 0.2-0.6 mM HP-β-CD. Furthermore, >90 % conversion ratio was reached per cycle through a co-cyclic-utilization method with HP-β-CD and immobilized ASP.

Conclusion: Cortisone acetate conversion ratio in the HP-β-CD cyclic-utilization method is promising for industrial applications. The method can also be expanded to other CDs and other hydrophobic compounds bioconversion.