Evaluación de resistencia de bacterias a los metales pesados, en la microcuenca del Rio Chibunga.

Abstract

The objective of this degree research was to evaluate the resistance to heavy metals Lead (Pb2 +), Chromium (Cr6 +), Cadmium (Cd2 +), and Mercury (Hg2 +) of bacterial isolates to obtain resistant clones and characterize. These were obtained from water samples from the Chibunga River Micro-Watershed. For this, bacterial clones were isolated from seven water samples from different points along the Micro-Watershed, using PCA (Plate Count Agar) culture medium supplemented with heavy metals to estimate bacterial growth in order to isolate the resistant bacteria. 32 clones were obtained which were stabilized and characterized by means of gram staining, being the gram bacteria negative which predominated. These clones were subjected to increasing concentrations of heavy metal to evaluate their resistance, of which 75% was resistant to lead up to a concentration of 2000 ug / ml, a 56% was resistant to chromium up to a concentration of 600 ug / ml, 25% was resistant to mercury up to the concentration of 1000 ug / ml, and 19% was resistant to cadmium up to 1000 ug / ml. In addition, 8 clones presented multi-resistance for all heavy metals in different concentrations, all of them from sample five. They were characterized by means of the biochemical tests nine clones, obtaining as a result that these belong to the genera Pseudomonas, Shigella, Proteus, Enterobacter and Staphylococcus. The results show that there are bacteria which resist several concentrations of heavy metal, also indicate that there is multi-resistance, so they can be used in processes of bioremediation of water contaminated with heavy metals. For this reason, it is recommended to research the efficiency of these bacteria in the remediation of environments contaminated with metals.