Análisis de la resistencia a estrés por metales pesados de levaduras aisladas del volcán Tungurahua, Ecuador.

Abstract

Contaminated with high concentrations of heavy metals ecosystems are a determining factor in the evolution of cell physiology of certain species of microorganisms, as they induce selection mechanisms that allow them to survive and adapt to changing conditions thereof, as it is the Tungurahua volcano. From the analysis of resistance to heavy metal stress of 10 strains of yeasts isolated from this volcanic ecosystem, could be obtained robust and viable species after treatment with increasing concentrations of heavy metals such as Zn, Cr, Cd, Pb, Ni and Cu. Metschnikowia and Rhodotorula pulcherrima were mucilaginous species showed great resilience to stress caused by all heavy metals under study, as they grew in media supplemented with; 2mM Zn, Pb, Ni and Cr, Cd and 0.2mm, and Cu, respectively. Against stress caused by a concentration of 2 mM Cu, 9 species of highly resistant yeasts and great cell viability was found, which is the metal most tolerated by the biota of the Tungurahua volcano. Despite the high toxicity of Cd, two strains of yeast was obtained; Rhodotorula mucilaginosa and Cryptococcus gastricus that were resistant to a significant amount of this metal 1mM. Three resistant to high concentrations of 10mM Zn strains were also found; Metschnikowia pulcherrima, Metschnikowia sp and Candida sake. With the results obtained yeast strains isolated from a natural source of environmental pollution, with the potential to tell the resistance to heavy metal stress becoming species suitable for application in bioremediation of polluted ecosystems with heavy metals such as Cu are displayed , Zn and Cd.