Fig.9
Mechanism of ZIF-8/RGO for DAADH immobilization was thought about
multi-level interactions include coordination bonds, hydrogen bonds,
electrostatic interactions and hydrophobic effect (Fig.10). There will
probably be coordination bonds, hydrogen bonds and electrostatic
interactions between DAADH and ZIF-8. Controllable immobilization of
DAADH within ZIF-8 was crucial for achieving efficient catalysis and
high stability. As for DAADH and RGO, it will be hydrophobic effect,
which can improve the stability. ZIF-8/RGO is showed to be a good
carrier for DAADH and the DAADH/ZIF-8/RGO has potential in biocatalysis
. Fig.10
3.10 One-step separation and immobilization of enzyme by
bimetal MOF
One-step separation and
immobilization of DAADH from crude enzyme solution by bimetal based MOF
was studied. Integrate of separation and immobilization of enzyme
directly from cell lysis solution in a single biomineralization step.
Bimetal-based MOF was developed to immobilize DAADH by nickel (Ni) and
zinc (Zn) ions. ZIF-8/RGO/Ni composite for in situ immobilization
of D-amino acid dehydrogenase obtained 1.5-fold activity of free enzyme.
Kinetic parameters of DAADH-ZIF-8/RGO/Ni-DAADH were calculated and the
results confirmed the enhancement of activity (Table 2).