Bioreactor Membranes for Laccase Immobilization Optimized by Ionic Liquids and Cross-Linking Agents

A novel concept of membrane bioreactor based on polymeric ionic liquids laccase membrane has been implemented in batch process for decolorization of the anthraquinonic dye Remazol Brillant Blue R (RBBR). New laccase immobilization strategy has been optimized by casting the enzyme into a polymeric inclusion membrane (PIM) using ionic liquids (ILs) and polyvinyl chloride (PVC) leading to laccase polymeric IL membrane (PILM). Four different ILs (1-octyl-3-metylimidazolium bis(trifluoromethylsulfonyl)imide, [OMIM][NTF₂]; cholinium bis(trifluoromethylsulfonyl)imide, [Ch ol][NTF₂]; cholinium dihydrogenphosphate, [Chol][H₂PO₄] and hydroxyethylammonium formate, [HEA][Fo]) have been screened and mixed to constitute the active phase of the support of PIM. This strategy has been fully succeeded since high laccase immobilization rates were recorded (about 98%) when using the optimal mixture containing three ILs (45% [OMIM][NTf₂]/5% [Chol][NTf₂]/2.5% [HEA][Fo]) and supplemented by 0.5% glutaraldehyde. It was found that such mixture contributes to increase the stability and reusability of laccase-PILM during eight successive assays in a batch discontinued stirred reactor. Decolorization rate of 75% has been reached in the batch decolorization process of RBBR with high reusability yield. Graphical Abstract Decolorization of RBBR by PILM_laccase.