title: Immobilized Candida antarctica lipase B on ZnO nanowires/macroporous silica composites for catalyzing chiral resolution of (R,S)-2-octanol.
abstract: ZnO nanowires were successfully introduced into a macroporous SiO2 by in situ hydrothermal growth in 3D pores. The obtained composites were characterized by SEM and XRD, and used as supports to immobilize Candida antarctica lipase B (CALB) through adsorption. The high specific surface area (233 m(2)/g) and strong electrostatic interaction resulted that the average loading amount of the composite supports (196.8 mg/g) was 3-4 times of that of macroporous SiO2 and approximate to that of a silica-based mesoporous material. Both adsorption capacity and the activity of the CALB immobilized on the composite supports almost kept unchanged as the samples were soaked in buffer solution for 48 h. The chiral resolution of 2-octanol was catalyzed by immobilized CALB. A maximum molar conversion of 49.1% was achieved with 99% enantiomeric excess of (R)-2-octanol acetate under the optimal condition: a reaction using 1.0 mol/L (R,S)-2-octanol, 2.0 mol/L vinyl acetate and 4.0 wt.% water content at 60°C for 8h. After fifteen recycles the immobilized lipase could retain 96.9% of relative activity and 93.8% of relative enantioselectivity.
authors.affiliation: Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, PR China.
authors.forename: Chuan-Yang
authors.initials: CY
authors.lastname: Shang
authors.affiliation: Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, PR China.
authors.forename: Wei-Xun
authors.initials: WX
authors.lastname: Li
authors.affiliation: Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, PR China. Electronic address: zhangruifeng@nbu.edu.cn.
authors.forename: Rui-Feng
authors.initials: RF
authors.lastname: Zhang
mesh_terms: D002175:Candida / Q000201:enzymology; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry; D036103:Nanotechnology; D053770:Nanowires / Q000737:chemistry / Q000648:ultrastructure; D000442:Octanols / Q000737:chemistry* / Q000378:metabolism*; D012822:Silicon Dioxide; D013237:Stereoisomerism; D013696:Temperature; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D000442:Octanols; C067943:2-octanol; D012822:Silicon Dioxide; D008049:Lipase; C431349:lipase B, Candida antarctica; D015034:Zinc Oxide
keywords: (R,S)-2-Octanol; Chiral resolution; Immobilized lipase; SiO(2) macroporous material; ZnO nanowires