Feasibility of Bioleaching of Selected Metals from Electronic Waste by Acidiphilium acidophilum

Abstract

The plausibility of bioleaching of selected metals, viz. Cu, Zn, Pb and Ni, from e-waste in the form of waste printed circuit board (PCB) from a television set was evaluated using a pure culture of Acidiphilium acidophilum, a strain of acidophilic alphaproteobacteria. Results from the study indicated that A. acidophilum was able to grow in the presence of e-waste and efficiently solubilize abundant metals like Cu as well as trace metals like Zn and Ni present in PCB. At a pulp density of 1 g/L with a particle size of <600 μm, maximum metal bioleaching efficiency of around 79% for Cu, 39% for Ni, 29% for Zn and 10% for Pb was observed at 60 days of leaching time. For Cu, bioleaching efficiency achieved at 45 days was around 78% which asymptotically increased to around 79% at 60 days. Similar asymptotic bioleaching trend was also observed for Ni, Zn and Pb. These findings highlight the practical feasibility of utilizing A. acidophilum for the successful development of bioleaching process for metal recovery from e-waste. However, the yield as well as leaching time can be improvised by optimizing various biotic and abiotic factors controlling the process.