Briefly, after performing classical enzyme immobilization (as always, in presence of PLP, i.e. 0.1 mM or 1 mM), a subsequent step of PLP immobilization was performed at lower ionic force in order to favor the co-factor grafting at the PEI-coated membrane surface. The resulting membrane was tested in 8 successive catalytic cycles without PLP addition, and exhibited much higher stability as compared to TA_PP3. In particular, TA_PP3_SS0.1 did not show any activity drop. That remarkable stability displayed by TA_PP3_ SS0.1 might be explained by the higher PLP loading achieved for this catalyst (0.97 µmol as compared to TA_PP3_ SS1 (0.85 µmol) (Table ). These results suggest that upon this two-step immobilization strategy (and employing 0.1 mM PLP for TA immobilization step), PLP is suitably provided to the enzyme (i.e. available for the transamination catalytic act) in satisfying amounts. It is noteworthy that performing TA immobilization with 0.1 mM (instead of 1 mM) of PLP also enabled to boost the TA loading and increase the overall activity, but it lowered the specific activity of the catalyst (Table , line 3). Finally, chiral HPLC analyses allowed us to confirm that the immobilization process did not affect the biocatalysts enantioselectivity (Table ). To this aim, the produced BMBA enantiomers obtained when employing the two best-performing immobilization strategies (namely TA_HPAN3b and TA_PP3) were analyzed and quantified. For all four membraneimmobilized TAs studied, only one BMBA enantiomer was detected, suggesting that the obtained biocatalytic membranes are enantioselective. Since the investigated reaction is a kinetic resolution (i.e. starting from a racemic mixture), the unconverted BMBA enantiomer (e.g. R-BMBA for HeWT, S-BMBA for TsRTA) was always detected by chiral HPLC (Figure -22).