Use of (Saccharomyces cerevisiae) Mutant in Bioremediation of Some Heavy Metals

Abstract

The study aimed to use of baker’s yeast Saccharomyces cerevisiae in Bioremediation of some heavy metals and improving its capability by mutation. The dried baker's yeast from Aldnaamaya China Company used in this study. The yeast subjected to serial diagnostic tests to ensure its belongings to S. cerevisiae. To improve the ability of the yeast to remove the metals, it was mutated by Nitrosoguanidine, and among different mutants, it was found that three of them designated as Sc6-1, Sc6-2 and Sc6-3, were more resistant to the antifungal cycloheximide in a concentration of 5 and 10 µg/ ml. These mutants were selected to study their efficiency to remove metals under the specific circumstances of attachment 10 minutes, pH 6, temperature 25○C, the stirring speed 150 rpm/ min, by using an inoculums size 1×106 cells/ ml in a solution containing 1mg/L of from each metal. it was found that the mutant Sc6-2 has gain an excellent efficiency to remove of chromium, nickel, cobalt, cadmium, lead, iron and copper in combined at a rate 72.23%, while the removal efficiency of these elements by the other mutants Sc6-1 and Sc6-3 were 64.67% and 65.37% respectively.