title: Chitosan-mediated formation of biomimetic silica nanoparticles: an effective method for manganese peroxidase immobilization and stabilization.
abstract: Our work here, for the first time, reported the use of chitosan-mediated biomimetic silica nanoparticles in enzyme immobilization. In order to make clear the relationship among silicification process, silica nanoparticle structure and immobilized enzyme activity, a mechanism of chitosan-mediated silicification using sodium silicate as the silica source was primarily evaluated. Chitosan was demonstrated effectively to promote the silicification not only in accelerating the aggregation rate of sodium silicate, but also in templating the formation of silica nanoparticles. Although the whole biomimetic silicification process contained polycondensation-aggregation-precipitation three stages, the elemental unit in precipitated silica was confirmed to be nanoparticles with 100 nm diameter regardless of the chitosan and silicate concentration used. Furthermore, the effect of enzyme on silicification process was also investigated. The introducing of manganese peroxidase (MnP) to silica precursor solution had no obvious effect on the silicification rate and nanoparticle morphology. The residual activity and embedding rate of immobilized MnP were 64.2% and 36.4% respectively under the optimum conditions. In addition, compared to native MnP, the MnP embedded in chitosan/silica nanoparticles exhibited improved stability against organic solvent and ultrasonic wave. After ultrasonic treatment for 20 min, 77% of the initial activity was remained due to the protective effect of chitosan/silica nanoparticles, while native MnP lost almost all of its original activity.
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Science, Beijing 100190, China; School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China.
authors.forename: Pan-Pan
authors.initials: PP
authors.lastname: Luan
authors.affiliation: School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China.
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Jiang
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Science, Beijing 100190, China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China.
authors.forename: Song-Ping
authors.initials: SP
authors.lastname: Zhang
authors.affiliation: School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Gao
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Science, Beijing 100190, China.
authors.forename: Zhi-Guo
authors.initials: ZG
authors.lastname: Su
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Science, Beijing 100190, China.
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Ma
authors.affiliation: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Science, Beijing 100190, China. Electronic address: zhangyf@ipe.ac.cn.
authors.forename: Yu-Fei
authors.initials: YF
authors.lastname: Zhang
mesh_terms: D032701:Biomimetics; D048271:Chitosan / Q000737:chemistry*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D010544:Peroxidases / Q000737:chemistry* / Q000378:metabolism; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012997:Solvents; D013010:Sonication; D014465:Ultrasonics
chemical_list: D004800:Enzymes, Immobilized; D017640:Silicates; D012997:Solvents; D012822:Silicon Dioxide; D048271:Chitosan; D010544:Peroxidases; C051129:manganese peroxidase; C005691:sodium silicate
keywords: Biomimetic silicification; Chitosan; Immobilization; Manganese peroxidase; Silica nanoparticle