Kinetics of biogenic sulfide production for microbial consortia isolated from soils with different bioaccessible concentrations of lead.

Labastida-Núñez Israel, Celis Berenice, Razo-Flores Elias, R. Cruz Roel, Lázaro Isabel, Briones-Gallardo Roberto.
International Journal of Environmental Science and Technology Vol. 10. Is: 4, pp827-836 Editorial. Springer-Verlag. Publicado impreso:04/06/2013, 2013.


Different technologies have been implemented for the treatment of acid mine drainage. Among these are technologies such as geochemical barriers and sulfidogenic reactors, which use biogenic sulfide (produced by sulfate-reducing bacteria) for metallic stabilization. Because both processes involve microorganisms, it is important to have a clear understanding of the factors that influence their activity in different toxic environments. Given that microbial communities isolated from polluted sites could have a higher tolerance to toxic ions, two consortia with sulfate-reducing activity were isolated from different soils impacted by mining activities. These soils had different total (401 and 19300 mg Pb kg-1), mobile (54 and 1415 mg Pb kg-1) and bioaccessible (316 and 3175 mg Pb kg-1) concentrations of lead. The kinetics of biogenic sulfide production for both consortia were monitored in a batch reactor after they were exposed to different initial lead concentrations. These lead concentrations were established based on the results of lead mobility tests. The estimated biogenic sulfide production rates and biomass concentrations of both consortia showed different responses to the presence of lead. Results highlighted that lead sulfide precipitation on microbial cell is a tolerance mechanism identified and this one is triggered for the lead bioaccessible concentrations threshold in soil. These results could be useful to the design of processes based in sulfate reducing activity for the removal or stabilization of metal present in water or soil, respectively.