Role of microorganisms in rehabilitation of mining sites, focus on Sub Saharan African countries

Pollutions associated with mining activities are environmentally challenging worldwide, particularly in Sub Saharan African countries due to extreme climatic conditions, influencing the dispersion of metallic pollutants in ecosystems. Mine tailings subjected to acid mine drainage or eolian erosion represent a major source of damages to the environment. Microorganisms play a key role in biogeochemical cycles controlling metals and metalloids fate and behavior in polluted environments. Some microorganisms accelerate the oxidative dissolution of sulfide minerals, leading to the formation of acid mine drainages. In another hand, microorganisms can favor the precipitation of toxic metals and metalloids in solution, contributing to the natural attenuation of polluted waters. These natural capacities can be exploited for the bioremediation of mine impacted sites. Microorganisms also play a key role in phytostabilisation, either indirectly by promoting plant growth or directly through metals and metalloids mobilization or immobilization in soils. Thus, microorganisms are important actors of mining sites remediation. Advances in the field of high throughput sequencing techniques have revolutionized molecular biology and opened a new era in research on microbial ecology, enabling to explore the diversity and activity of microbial communities thriving in polluted environments. In-depth understanding of microbial activity will contribute to improve the mitigation of pollutions. In this work, we review the progress made in using microorganisms to remediate acid mine drainage pollutions, with emphasis on bioremediation case studies in Sub Saharan Africa. The study also highlights the role of microbial communities in the phytoremediation of mine tailings.