title: Biorecovery of gold by Escherichia coli and Desulfovibrio desulfuricans.
abstract: Microbial precipitation of gold was achieved using Escherichia coli and Desulfovibrio desulfuricans provided with H2 as the electron donor. No precipitation was observed using H2 alone or with heat-killed cells. Reduction of aqueous AuIII ions by both strains was demonstrated at pH 7 using 2 mM HAuCl4 solution and the concept was successfully applied to recover 100% of the gold from acidic leachate (115 ppm of AuIII) obtained from jewelry waste. Bioreductive recovery of gold from aqueous solution was achieved within 2 h, giving crystalline Au0 particles (20-50 nm), in the periplasmic space and on the cell surface, and small intracellular nanoparticles. The nanoparticle size was smaller (red suspension) at acidic pH (2.0) as compared to that obtained at pH 6.0 and 7.0 (purple) and 9.0 (dark blue). Comparable nanoparticles were obtained from AuIII test solutions and jewelry leachate.
authors.affiliation: Unit of Functional Biomaterials, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: K
authors.initials: K
authors.lastname: Deplanche
authors.forename: L E
authors.initials: LE
authors.lastname: Macaskie
mesh_terms: D003247:Conservation of Natural Resources / Q000379:methods; D045285:Desulfovibrio desulfuricans / Q000378:metabolism* / Q000648:ultrastructure; D004926:Escherichia coli / Q000378:metabolism* / Q000648:ultrastructure; D006046:Gold / Q000737:chemistry / Q000378:metabolism*; D017612:Gold Compounds / Q000737:chemistry / Q000378:metabolism; D006851:Hydrochloric Acid / Q000737:chemistry; D007220:Industrial Waste; D008669:Metallurgy; D046529:Microscopy, Electron, Transmission; D017942:Nitric Acid / Q000737:chemistry; D010084:Oxidation-Reduction; D010316:Particle Size; D014961:X-Ray Diffraction
chemical_list: D017612:Gold Compounds; D007220:Industrial Waste; D017942:Nitric Acid; D006046:Gold; D006851:Hydrochloric Acid; C022102:aqua regia