Stable and Reusable Fe3O4/ZIF-8 Composite for Encapsulation of FDH Enzyme under Mild Conditions Applicable to CO2 Reduction

The enzymatic reduction of carbon dioxide presents limited applicability due to denaturation and the impossibility of biocatalyst recovery; disadvantages that can be minimized by its immobilization. Here, a recyclable bio-composed system was constructed by in-situ encapsulation under mild conditions using formate dehydrogenase in a ZIF-8 metalorganic framework (MOF) in the presence of magnetite. The partial dissolution of ZIF-8 in the enzyme's operation medium can be relatively inhibited if the concentration of magnetic support used exceeds 10 mg mL(-1). The bio-friendly environment for immobilization does not harm the integrity of the biocatalyst, and the production of formic acid is improved 3.4-fold compared to the free enzyme because the MOFs act as concentrators of the enzymatic cofactor. Furthermore, the bio-composed system retains 86 % of its activity after a long time of five cycles, thus indicating an excellent magnetic recovery and a good reusability.

Automated summary

A recyclable bio-composed system was constructed by encapsulating formate dehydrogenase in a ZIF-8 metalorganic framework (MOF) with the presence of magnetite, which overcomes the limitations of enzyme denaturation and the impossibility of biocatalyst recovery. The partial dissolution of ZIF-8 in the enzyme's operation medium can be inhibited by using a magnetic support concentration exceeding 10 mg mL(-1). The bio-friendly immobilization environment does not harm the integrity of the biocatalyst and improves the production of formic acid 3.4-fold compared to the free enzyme due to the concentration effect of MOFs as enzymatic cofactor concentrators. Furthermore, the bio-composed system retains 86% of its activity after five cycles, indicating excellent magnetic recovery and reusability.