Réactifs biosourcés pour la flottation des minerais dans l’industrie minière

Biosourced reagents for the flotation of minerals in the mining industry Mining companies are forced to exploit ore bodies that are more complex and of lower grade while complying with increasingly challenging environmental regulations. Many of those companies use froth flotation to concentrate mineral ores. In this process, often toxic chemicals are added to specifically alter mineral surface properties (mainly hydrophobicity). With increasing regulatory restrictions, the industry could face a dead end with no alternative reagents that are sufficiently efficient, low cost or environment friendly.
This project aims at the development of such alternative, by using the known chemical diversity of peptides to develop new bio-reagents for gold and silver, copper, zinc, nickel sulfides flotation for the mining industry. Those reagents would be relatively easy to treat in the effluent, pose little threat to human health and offer good mineral selectivity. To this end, following 1) a large-scale screen of combinatorial peptide libraries and 2) modeling, simulating and designing optimal bioflotation reagents, 3) two approches will be followed to produce them, either 3a) soluble protein production by fermentation or 3b) the use of recombinant microorganism membrane fragments. Ultimately, 4) a panel of the best biocollectors will be tested at different scale up to a flottation cell able to treat 1 kg of mineral mixture in batch.
1) Peptide library screening will be performed using the phage display technology. To this end, billions of different amino acid sequences will be screened using New England Biolabs (NEB) protocols. These screens will be completed by performing DNA amplification of adsorbed sequences, large spectrum sequencing (using deep sequencing tools) to determine, using multivariate statistics and machine learning the most promising peptides. 2) molecular modeling will allow to test these best sequences in silico interacting with mineral surfaces by adding different hydrophobic domains to predict and optimize their flotation potential. 3) Important efforts will be devoted to reduce production costs of these bioreagents by optimizing fermentation processes, maximizing yields and minimizing substrate costs. A recombinant strain, expressing the bioreagent at its surface will also be constructed in order to test the addition of membrane fragments to flotation processes. Finally, 4) different instruments will be utilized to test a set of best bio-reagents in real life conditions.
At the end of this project, new bio-collectors with improved efficiency, smaller environment footprint and competitive costs will be available for industrial and commercial development by the mining industry.