Presence of mercury-resistant rhizosphere bacteria in soils in the Southern Bolívar, Colombia

Abstract

The objective of the present study was to isolate rhizospheric bacteria from samples from the Santa Cruz Mine, department of Bolívar, in order to evaluate in vitro resistance activity at different concentrations of mercury. The samples were collected randomly from different sites near the Santa Cruz gold mine, from which they isolated rhizospheric bacteria. The resistance capacity of bacteria at different concentrations of mercury in the form of mercury chloride (HgCl2) at concentrations of 50 ppm, 100 ppm, 150 ppm, 200 ppm and 250 ppm was evaluated in vitro; also the bacteria resistant to this metal were used to evaluate the ability to promote growth in plants. The results showed that the bacterium identified as Pseudomonas luteola, resisted in vitro at 200 ppm of mercury chloride (HgCl2), and qualitatively had the ability to produce siderophores and biologically fix nitrogen. P luteola was isolated from the rhizosphere near the Santa Cruz mine in the department of Bolívar, Colombia, with soils with high concentrations of mercury and extremely acidic soil reaction.

Keywords

• Bacteria
• rizósfera
• mercurio
• resistencia.