Simultaneous advancement of biocatalytic activity and mass transport in aminated membrane reactors

Continuous-flow enzyme reactors face major challenges that limit enzymes' industrial use. In case of enzyme membrane reactors (EMRs), the poor performance mainly results from difficulty in achieving high enzyme loading amount, activity recovery, reusability, and unit permeability at the same time. Herein, we propose a novel type of aminated EMR support for fouling-induced enzyme immobilization, obtained by two-step covalent modification of polysulfone (PSF) precursor with polyethyleneimine (PEI) prior to casting by phase inversion. Adding positively charged immobilization sites eliminated the need to reduce pore size for effective enzyme retention - enabling high biocatalytic activity and good mass transport in the same reactor, without compromising each other. The productivity of EMRs with immobilized laccase, carbonic anhydrase (CA), and horseradish peroxidase (HRP) increased by over 1.4-, 6-, and 36-fold, respectively, compared to using commercial PSF and polyethersulfone (PES) supports; showing permeabilities above 2600 LMH.bar −1 and steady continuous operation with minimal enzyme loss (<5 % in total). Considering simplicity and versatility of the method, our findings could expand the potential of immobilized enzymes for a wide range of applications in biosynthesis.