title: Evidence of cell surface iron speciation of acidophilic iron-oxidizing microorganisms in indirect bioleaching process.
abstract: While indirect model has been widely accepted in bioleaching, but the evidence of cell surface iron speciation has not been reported. In the present work the iron speciation on the cell surfaces of four typically acidophilic iron-oxidizing microorganism (mesophilic Acidithiobacillus ferrooxidans ATCC 23270, moderately thermophilic Leptospirillum ferriphilum YSK and Sulfobacillus thermosulfidooxidans St, and extremely thermophilic Acidianus manzaensis YN25) grown on different energy substrates (chalcopyrite, pyrite, ferrous sulfate and elemental sulfur (S(0))) were studied in situ firstly by using synchrotron-based micro- X-ray fluorescence analysis and X-ray absorption near-edge structure spectroscopy. Results showed that the cells grown on iron-containing substrates had apparently higher surface iron content than the cells grown on S(0). Both ferrous iron and ferric iron were detected on the cell surface of all tested AIOMs, and the Fe(II)/Fe(III) ratios of the same microorganism were affected by different energy substrates. The iron distribution and bonding state of single cell of A. manzaensis were then studied in situ by scanning transmission soft X-ray microscopy based on dual-energy contrast analysis and stack analysis. Results showed that the iron species distributed evenly on the cell surface and bonded with amino, carboxyl and hydroxyl groups.
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.|Key Lab of Biometallurgy of Ministry of Education of China, Central South University, Changsha, 410083, China.
authors.forename: Zhen-yuan
authors.initials: ZY
authors.lastname: Nie
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.|Key Lab of Biometallurgy of Ministry of Education of China, Central South University, Changsha, 410083, China.
authors.forename: Hong-chang
authors.initials: HC
authors.lastname: Liu
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China. jlxia@csu.edu.cn.|Key Lab of Biometallurgy of Ministry of Education of China, Central South University, Changsha, 410083, China. jlxia@csu.edu.cn.
authors.forename: Jin-lan
authors.initials: JL
authors.lastname: Xia
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.|Key Lab of Biometallurgy of Ministry of Education of China, Central South University, Changsha, 410083, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai, 201800, China.|Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China.
authors.forename: Xiang-jun
authors.initials: XJ
authors.lastname: Zhen
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai, 201800, China.|Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China.
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Zhang
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.|Key Lab of Biometallurgy of Ministry of Education of China, Central South University, Changsha, 410083, China.
authors.forename: Guan-zhou
authors.initials: GZ
authors.lastname: Qiu
mesh_terms: D041541:Acidianus / Q000378:metabolism*; D042763:Acidithiobacillus / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D004734:Energy Metabolism; D005296:Ferrous Compounds / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D013440:Sulfides / Q000378:metabolism; D013499:Surface Properties; D056928:X-Ray Absorption Spectroscopy
chemical_list: D005296:Ferrous Compounds; D013440:Sulfides; C012819:chalcopyrite; C011342:pyrite; C020748:ferrous sulfate; D003300:Copper; D007501:Iron
keywords: Bioleaching; In situ; Iron speciation; Iron-oxidizing microorganism; Synchrotron radiation