Remoción de plomo por rizobacterias aisladas de humedales: efecto de factores implicados en el proceso.

The presence of heavy metals in domestic and industrial effluents is a worldwide problem and its solution is a challenge for the environmental sanitation. For the elimination of metallic species from contaminated effluents, biological systems such as microorganisms constitute an ecological and efficient alternative. In the present research the ability of rhizobacteria to remove Pb2+ present in aqueous solutions, the effect of contact time and pH in the process was determined. Twenty-four bacterial strains isolated from the rhizosphere of the plants Heliconia rostrata and Cyperus sp. planted in artificial wetlands and Typha dominguensis, a plant belonging to natural wetlands, were used. All the bacterial biomasses showed capacity to remove lead and the 84.61 % of them achieved to uptake concentrations greater than 20 mg.g-1 of the metal. In three of the most promising rhizobacteria the speed of the process was evident, being enough 0.5h to reach uptake percentages between 36.8 and 85.5 %. In addition, they presented at pH 6.0 the highest Pb2+ removal with values from 29 to 35.8 mg.g-1. These results indicate the potential of rhizobacteria to be use in the elimination or reduction of lead contamination in wastewater. [ABSTRACT FROM AUTHOR]