Recovering precious metals contained in e-waste thanks to bacteria

Link to the interview of Dr. P. Rossi on RTS la 1ère

Preliminary studies and bioleaching experiments carried out to date by the CEL demonstrated the potential of complex bacterial communities in laboratory conditions to recover technology critical elements from electronic waste (e-waste). Elements such as cobalt, lithium, aluminum, copper, as well as REEs such as indium, neodymium and dysprosium were retrieved efficiently from e-waste made up of mobile phones. The effectiveness is still relative with respect to the recovery of gallium, silver and gold. Nevertheless, these initial experiments showed that this biological process does not require important amounts of energy and does not produce harmful gas emissions. These experiments were carried out at standard temperature and atmospheric pressure, without the need for environmentally damaging reagents, producing low amounts of secondary pollution.In this project, the aim was to assess the capacity of complex acidophilic microbial communities for the bio-leaching of e-waste, using conditions approaching those required for industrial full-scale operations. This study follows three goals, such as i) the isolation of efficient acidophilic metal-oxydizing bacterial consortia ii) the building of a low-cost and scalable biotrickling fermenters for e-waste leaching, and finally iii) the running of this fermenter in continuous mode, with efficient metal leaching. Analysis involve amplicon sequencing of the communities and detailed chemical characterization of the leachate composition. Finally, this bioleaching technique would contribute to the management of important metal resources and strategic components, which are required for the development of a society based on energy saving strategies and durable energy resource.