Polydopamine-mediated preparation of an enzyme-immobilized microreactor for the rapid production of wax ester

In our study, a polytetrafluoroethylene (PTFE) open-tubular enzyme-immobilized microreactor has been successfully prepared using dopamine polymerization and multi-layer deposition. The polydopamine layer was utilized as a primer layer in the microchannel to provide PTFE surface reactable groups, and polyethylenimine and Candida antarctica lipase B were alternatively adsorbed on the PTFE surface by the layer-by-layer method. The lipase loading kept increasing as the number of layers increased and reached a plateau at the 8th layer. The formation of multilayers and increase of enzyme loading were described and explained by the water contact angle measurement, Fourier transform infrared spectroscopy (FI-IR), and X-ray photoelectron spectroscopy, while the morphological characteristics were observed using Atomic Force Microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). Preparation of a wax ester using the microreactor had much better production efficiency (35 minutes to reach 95% yield) than that using traditional reactors (over 4 hours to complete the reaction). Very excellent stability can be achieved by the microreactor, which could be used for 144 hours with the residual activity remaining at 83% of the initial activity.