Biorefinery of olive leaves to produce dry oleuropein aglycone: use of homemade ceramic capillary biocatalytic membranes in a multiphase system

Oleuropein aglycone is an important antioxidant compound produced during oleuropein hydrolysis, not yet commercially available. Its production from renewable material by green processes is a challenge because it permits waste re-use and low environmental impact. In this work, homemade asymmetric capillary ceramic membranes were used to develop biocatalytic membranes, which were further used to produce oleuropein aglycone from olive leaves and/or commercial oleuropein. Results indicated that the biocatalytic system (containing covalently immobilized β-glucosidase) promotes the hydrolysis of oleuropein in both monophase and multiphase processes. Furthermore, the multiphase biocatalytic system enables the extraction of the hydrophobic oleuropein aglycone in an organic phase, before its rearrangement in water. This was achieved by the production, of an unstable water-in-oil emulsion (permeate side), on the basis of membrane emulsification process. The intensified biocatalytic/extractor system allowed taking shelter the hydrophobic compound in the organic phase with good efficiency (90%), protecting it from rearrangement.