Biorecovery of gold by Escherichia coli and Desulfovibrio desulfuricans

• Published in: Biotechnology and bioengineering Vol. 99; no. 5; pp. 1055 - 1064
• Main Authors: Deplanche, K, Macaskie, L.E
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-04-2008; Wiley; Wiley Subscription Services, Inc
• Subjects: Aqueous solutions; Bioconversions. Hemisynthesis; Biological and medical sciences; bioreduction; Biotechnology; Cells; Conservation of Natural Resources - methods; Desulfovibrio desulfuricans; Desulfovibrio desulfuricans - metabolism; Desulfovibrio desulfuricans - ultrastructure; E coli; Escherichia coli; Escherichia coli - metabolism; Escherichia coli - ultrastructure; Fundamental and applied biological sciences. Psychology; Gold; Gold - chemistry; Gold - metabolism; Gold Compounds - chemistry; Gold Compounds - metabolism; gold recovery; gold reduction; Hydrochloric Acid - chemistry; Industrial Waste; Metallurgy; Methods. Procedures. Technologies; Microscopy, Electron, Transmission; Nanoparticles; Nitric Acid - chemistry; Oxidation-Reduction; Particle Size; X-Ray Diffraction; Gold; Desulfovibrio desulfuricans; Reduction; gold reduction; gold recovery; Biotransformation; Escherichia coli; Bacteria; bioreduction; Enterobacteriaceae
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.21688

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 Au(III) 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 Au(III)) obtained from jewellery waste. Bioreductive recovery of gold from aqueous solution was achieved within 2 h, giving crystalline Au(0) 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 Au(III) test solutions and jewellery leachate. Biotechnol. Bioeng. 2008;99: 1055-1064.