4. Conclusion
MOFs, with extremely high specific surface area, abundant porosity and
extraordinary multi-functionality, hold a great promise as matrices for
enzyme immobilization with biocompatibility and high protein loading
capacity and enhance the cost-efficiency of biocatalysis. The D-amino
acid dehydrogenase connected with (RTHRK)4 was
constructed. Combined with peptide linker and MOF, efficient enzyme
immobilization was achieved by encapsulation of DAADH via a facile
one-step biomimetic mineralization strategy. These results indicated the
interactions of MOF and peptide linker substantially improved the
catalytic efficiency and stability of DAADH. After 10 hours of
incubation at 50 °C, DAADH/ZIF-8/RGO retained 53.4% relative activity
while that is 37.8% for DAADH/ZIF-8, and the free enzyme was almost
inactivated. After 7 recycles, the residual activities of
DAADH/ZIF-8/RGO and DAADH/ZIF-8 were 64.3% and 45.6%, respectively.
Furthermore, one-step separation and immobilization by
DAADH-ZIF-8/RGO/Ni-DAADH was carried out with 1.5-fold activity
enhancement. Hybrid materials of MOF and carbon materials also can be
extended for the multi-enzyme immobilization, which have potential in
biocatalysis.