Metal–Organic Framework Encapsulation of Ferulic Acid Decarboxylase: Robust Biocomposites Catalyzing Synthetically Useful Decarboxylation and Synergized CO ₂ Fixation Reactions

Ferulic acid decarboxylases (FDCs) are promising enzymes for the catalysis of synthetically useful decarboxylations as well as CO2 fixation reactions in a sustainable manner. However, temperature and light instability of the enzyme are major concerns. Moreover, unfavorable thermodynamic barrier toward carboxylation direction limits enzyme’s ability for CO2 fixation reactions. Here, by in situ immobilization of FDC from Capronia coronata (CcFDC) inside ZIF-type metal–organic frameworks (MOFs), we obtained robust catalytic biocomposites, i.e., CcFDC@MOFs. Among the three types of CcFDC@MOFs tested, CcFDC@ZIF-67 exhibited excellent advantages compared to the free enzyme, with impressive thermal and light stability, higher turnover numbers, a broad temperature optimum extending into 75 °C and high reusability in decarboxylation reactions. Moreover, CcFDC@ZIF-67 can catalyze CO2 fixation reactions more efficiently than the free enzyme, which indicates that CcFDC@ZIF-67 has the potential to act as both a bicarbonate/CO2 capturing material and a CO2 fixation catalyst. We further improved carboxylation yields by sequential batch and semiflow reaction designs, with the semiflow design exhibiting 13-fold increase in total turnover numbers and 15-fold increase in space-time yields over the batch reaction, demonstrating CcFDC@ZIF-67’s ability as a bifunctional biocomposite for CO2 capture and conversion.