Chromium resistant yeast with multi-metal resistance isolated from industrial effluents and their possible use in microbial consortium for bioremediation of wastewater

Chromium (Cr) resistant yeasts with minimum inhibitory concentration of Cr6+ of 2.0 mg/mL were isolated from industrial effluents of tanneries, which could also tolerate 1.0-1.3 mg/mL of Pb2+ 0.6-0.8 mg/mL of Cd2+ and Cu2+, 0.4-0.5 mg/mL of Co2+, 0.3-0.6 mg/mL of Ni2+ 0.2 mg/mL of Hg2+ and 0.3-0.5 mg/mL of Zn2+. The isolates showed optimum growth at 30 degrees C and pH 5.5-6.0. All yeast isolates showed typical growth pattern except for the lag phase which got extended in the presence of Cr. The yeast isolates could remove 65-80% of Cr6+ from the medium after 72 hours of incubation. The yeast isolates absorbed 25-35% of Cr6+ whereas 30-40% of the Cr6+ was adsorbed on the cell surface. The yeast isolates can be exploited for bioremediation of chromium containing wastes, since they seem to have the potential to accumulate the toxic metal from the environment.