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 CO 2 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 CO 2 fixation reactions. Here, by in situ immobilization of FDC from Capronia coronata ( Cc FDC) inside ZIF-type metal–organic frameworks (MOFs), we obtained robust catalytic biocomposites, i.e., Cc FDC@MOFs. Among the three types of Cc FDC@MOFs tested, Cc FDC@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, Cc FDC@ZIF-67 can catalyze CO 2 fixation reactions more efficiently than the free enzyme, which indicates that Cc FDC@ZIF-67 has the potential to act as both a bicarbonate/CO 2 capturing material and a CO 2 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 Cc FDC@ZIF-67’s ability as a bifunctional biocomposite for CO 2 capture and conversion.