title: Biodesulfurization of dibenzothiophene by microbial cells coated with magnetite nanoparticles.
abstract: Microbial cells of Pseudomonas delafieldii were coated with magnetic Fe3O4 nanoparticles and then immobilized by external application of a magnetic field. Magnetic Fe3O4 nanoparticles were synthesized by a coprecipitation method followed by modification with ammonium oleate. The surface-modified Fe3O4 nanoparticles were monodispersed in an aqueous solution and did not precipitate in over 18 months. Using transmission electron microscopy (TEM), the average size of the magnetic particles was found to be in the range from 10 to 15 nm. TEM cross section analysis of the cells showed further that the Fe3O4 nanoparticles were for the most part strongly absorbed by the surfaces of the cells and coated the cells. The coated cells had distinct superparamagnetic properties. The magnetization (delta(s)) was 8.39 emu.g(-1). The coated cells not only had the same desulfurizing activity as free cells but could also be reused more than five times. Compared to cells immobilized on Celite, the cells coated with Fe3O4 nanoparticles had greater desulfurizing activity and operational stability.
authors.affiliation: Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box No. 353, Beijing, 100080 China.
authors.forename: GuoBin
authors.initials: G
authors.lastname: Shan
authors.forename: JianMin
authors.initials: J
authors.lastname: Xing
authors.forename: HuaiYing
authors.initials: H
authors.lastname: Zhang
authors.forename: HuiZhou
authors.initials: H
authors.lastname: Liu
mesh_terms: D001422:Bacterial Adhesion; D001709:Biotechnology / Q000379:methods; D018914:Cells, Immobilized; D020099:Coated Materials, Biocompatible; D007692:Diatomaceous Earth; D052203:Ferrosoferric Oxide; D007501:Iron / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D011549:Pseudomonas / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D013455:Sulfur / Q000378:metabolism*; D013876:Thiophenes / Q000378:metabolism*
chemical_list: D020099:Coated Materials, Biocompatible; D010087:Oxides; D013876:Thiophenes; D007692:Diatomaceous Earth; D013455:Sulfur; D007501:Iron; D052203:Ferrosoferric Oxide; C016366:dibenzothiophene