Abstract
Charting, understanding, and exploring the broad range of microbial species present on and close to mined environments is revealing a plethora of interesting metabolisms. Microorganisms that survive in these extreme and often hostile environments can withstand high concentrations of metals through specialized pathways, metabolic responses, production of chelating and binding molecules, and processes such as bacterial induced metal/mineral precipitation. These native mine site microorganisms can be used to achieve more effective and sustainable bioremediation processes to stabilize mine waste for long-term storage on the mine site or to extract value from mine waste containing economically important metals. Since enrichment, isolation and screening of native microorganisms can be laborious and expensive, we are using genomics informed approaches to guide the selection of mine samples and their enrichment. Genomic mapping was performed on a wide range of samples from waste rock and tailings at mine sites in Canada and the U.S.A. Sample selection was based on the microbial population compositions, which also guided growth medium selection. Screening protocols for targeted enzymatic processes were developed based on simple pH and oxidation- reduction reactions. Native microbial strains were recovered with the capability to remove copper from solution, and to precipitate carbonates and increase the mechanical strength of tailings. These native microorganisms will be used in nature-based processes for recovery of metals from certain wastes with high residual value as one application, and to stabilize mine wastes as another application.