Characterization of Saccharomyces cerevisiae Mutants Resistant to High Concentrations of Co2+: A Primary Step to Bioremediation by Removal and Recovery of Co2+ from Waste Waters

1041 Heavy metals represent an important environmental problem due to their potential toxic effects, and their accumulation throughout the food chain leads to serious ecological and health problems. The increase of environment pollution by heavy metals generated the interest to the problem of live organisms resistance to these metals. Biosorption is one of the mechanisms of microorganisms resistance to heavy metals and yeasts as biosorbents are of special interest [1-4]. The most well-known and commercially significant yeasts are the related species and strains of Saccharomyces cerevisiae. Although this microorganism is commonly used as baker’s yeast and for some type of fermentation, its potential as bioremediation effector is more and more studied [5-6]. Saccharomyces cerevisiae is an excellent model system to study the uptake and accumulation of heavy metals by living cells. This simple organism can grown on low-cost media, can be manipulated easily, and is not pathogenic. Its genome has been entirely sequenced and many cellular processes have been identified at molecular level. In this work we focused on obtaining Saccharomyces cerevisiae mutants that are resistant to high concentrations of Co2+ in their environment, as primary step in designing a bioremediation system suitable for Co2+-contaminated environments. Although Co2+ is an essential micronutrient as a cofactor of vitamin B12 [7] and various other enzymes in animals, yeasts, bacteria, Archaea, and plants [8], exposure to inorganic Co2+ is associated with various human diseases such as contact dermatitis [9], allergic asthma, leading to subsequent interstitial fibrosis [10] and lung cancer [11]. Cobalt increases oxidative stress in cells by raising the concentration of reactive oxygen species [12] and mimics or replaces ions such as magnesium and calcium in various essential reactions [13]. Metal remediation through common physico-chemical techniques is expensive and unsuitable in case of voluminous effluents containing complexing organic matter and low metal contamination. Alternative biotechnological approaches received great deal of attention and growing metal-resistant cells that accumulate Characterization of Saccharomyces cerevisiae Mutants Resistant to High Concentrations of Co2+: A Primary Step to Bioremediation by Removal and Recovery of Co2+ from Waste Waters