Flavonoid esters synthesis using novel biocatalytic systems - CAL B immobilized onto LifeTech™ ECR supports

Abstract

In order to enhance productivity and cost-effectiveness of current lipase-catalyzed processes of flavonoid esters synthesis, different LifeTech™ ECR carriers varying in functional groups, polarity and porosity were hereby screened as immobilization supports for free lipase B from Candida antarctica. The most prospective ones were examined in esterification of three flavonoid glycoside representatives - phloridzin, naringin and esculin using different acyl donors. Highly active preparations were obtained by using hydrophobic C18 (ECR 8806M), epoxy/butyl (ECR 8285F) and primary amino (ECR 8409F) functionalized resins. Interestingly, lipase immobilized via hydrophobic interactions and covalent bonds exhibited high catalytic activity in esterification reactions using oleic acid as well as natural oils as acyl donors, yielding more than 70 % and 50 % conversion degree, respectively. On the other hand, lipase immobilized onto amino-support by electrostatic interactions, which demonstrated the highest hydrolytic activity, showed poor efficiency in ester syntheses. Operational stability study proved exceptionally high potential of lipases immobilized on epoxy-support or hydrophobic support for reproducible and cost-effective industrial application, since 90 % of initial activity was preserved after six consecutive reaction cycles of oleyl ester synthesis, while within following nine reuses, only moderate activity loss occurred. Moreover, besides very good esterifying activity, lipase immobilized via hydrophobic interactions showed outstanding operational stability during ten reuses in reaction of phloridzin transesterification with coconut oil.