title: Preparation and characterization of monodispersed microfloccules of TiO₂ nanoparticles with immobilized multienzymes.
abstract: Microfloccules of TiO(2) nanoparticles, on which glycerol-dehydrogenase (GDH), 1,3-propanediol-oxidoreductase (PDOR), and glycerol-dehydratase (GDHt) were coimmobilized, were prepared by adsorption-flocculation with polyacrylamide (PAM). The catalytic activity of immobilized enzyme in the glycerol redox reaction system, the enzyme leakage, stabilities of pH and temperature, as well as catalytic kinetics of immobilized enzymes relative to the free enzymes were evaluated. Enzyme loading on the microfloccules as much as 104.1 mg/g TiO(2) (>90% loading efficiency) was obtained under the optimal conditions. PAM played a key role for the formation of microfloccules with relatively homogeneous distribution of size and reducing the enzyme leakage from the microfloccules during the catalysis reaction. The stabilities of GDH against pH and temperature was significantly higher than that those of free GDH. Kinetic study demonstrated that simultaneous NAD(H) regeneration was feasible in glycerol redox system catalysted by these multienzyme microfloccules and the yield of 1, 3-popanediol (1, 3-PD) was up to 11.62 g/L. These results indicated that the porous and easy-separation microfloccules of TiO(2) nanoparticles with immobilized multienzymes were efficient in term of catalytic activity as much as the free enzymes. Moreover, compared with free enzyme, the immobilized multienzymes system exhibited the broader pH, higher temperature stability.
authors.affiliation: School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China. wuminnj@163.com
authors.forename: Min
authors.initials: M
authors.lastname: Wu
authors.forename: Qin
authors.initials: Q
authors.lastname: He
authors.forename: Qianfei
authors.initials: Q
authors.lastname: Shao
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Zuo
authors.forename: Fen
authors.initials: F
authors.lastname: Wang
authors.forename: Henmei
authors.initials: H
authors.lastname: Ni
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000327:Adsorption; D000426:Alcohol Dehydrogenase / Q000737:chemistry / Q000378:metabolism; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D006836:Hydro-Lyases / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D013401:Sugar Alcohol Dehydrogenases / Q000737:chemistry / Q000378:metabolism; D013696:Temperature; D014025:Titanium / Q000737:chemistry*; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D000426:Alcohol Dehydrogenase; D004800:Enzymes, Immobilized; D006836:Hydro-Lyases; D013401:Sugar Alcohol Dehydrogenases; D014025:Titanium; D000099166:Polyacrylamides; C009495:titanium dioxide; C052370:1,3-propanediol dehydrogenase; C020672:glycerol dehydrogenase; C020671:glycerol dehydratase