title: Bioleaching of a low-grade nickel-copper sulfide by mixture of four thermophiles.
abstract: This study investigated thermophilic bioleaching of a low grade nickel-copper sulfide using mixture of four acidophilic thermophiles. Effects of 0.2g/L l-cysteine on the bioleaching process were further evaluated. It aimed at offering new alternatives for enhancing metal recoveries from nickel-copper sulfide. Results showed a recovery of 80.4% nickel and 68.2% copper in 16-day bioleaching without l-cysteine; while 83.7% nickel and 81.4% copper were recovered in the presence of l-cysteine. Moreover, nickel recovery was always higher than copper recovery. l-Cysteine was found contributing to lower pH value, faster microbial growth, higher Oxidation-Reduction Potential (ORP), higher zeta potential and absorbing on the sulfide surfaces through amino, carboxyl and sulfhydryl groups. X-ray Diffraction (XRD) patterns of leached residues showed generation of S, jarosite and ammoniojarosite. Denaturing Gradient Gel Electrophoresis (DGGE) results revealed that l-cysteine could have variant impacts on different microorganisms and changed the microbial community composition dramatically during nickel-copper sulfide bioleaching.
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, Hunan 410083, China.
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Li
authors.affiliation: School of Life Science, Central South University, Changsha 410012, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhong
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
authors.forename: Yuehua
authors.initials: Y
authors.lastname: Hu
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, Hunan 410083, China.
authors.forename: Jiancun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China. Electronic address: zghe@csu.edu.cn.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: He
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha, Hunan 410083, China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Gu
mesh_terms: D001105:Archaea / Q000187:drug effects / Q000378:metabolism*; D001673:Biodegradation, Environmental / Q000187:drug effects; D003300:Copper / Q000302:isolation & purification*; D003545:Cysteine / Q000494:pharmacology; D058645:Denaturing Gradient Gel Electrophoresis; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D009532:Nickel / Q000302:isolation & purification*; D010100:Oxygen / Q000378:metabolism; D025341:Principal Component Analysis; D013055:Spectrophotometry, Infrared; D055672:Static Electricity; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D003300:Copper; D009532:Nickel; C017558:nickel sulfide; D003545:Cysteine; D010100:Oxygen
keywords: Bioleaching; Nickel–copper sulfide; Thermophiles; l-Cysteine