RESISTANCE OF RHODOTORULA RUBRA g2/1 TO HEAVY METALS AND THEIR ADSORPTION

Abstract

The aim was to study the level of resistance of the strain Rhodotorula rubra g2/1 to the heavy metals Cu, Zn, Pb, Cd and adsorption of them by the yeast cells. Red yeast strain Rhodotorulla rubra g2/1 was isolated by seeding on nutrient medium Saburo from the coastal waters of the Zmiiniy Island. The estimation of the influence of ions of heavy metals on physiology of yeast growth was conducted on Reader medium with addition of various concentrations of heavy metals Cu, Zn, Pb, Cd. The content of the metals in the investigated samples was determined with the atomic absorption spectrophotometer “Saturn-2”. The minimal concentrations of heavy metals inhibited the growth of yeast strain Rhodotorula rubra g2/1 were determined. They are 750 mg/l for copper, 500 mg/l for zinc, 120 mg/l for lead, 10 mg/l for cadmium. Thus, the studied yeast strain is the most resistant to copper and the most sensitive to cadmium. During incubation of the yeast in solutions containing heavy metals for 2 hours they remove 85.6% of copper, 18.6% of lead, 7.8% of cadmium, 7.7% of zinc. One gram of dry yeast biomass accumulates 90.0 mg of copper, 38.9 mg of cadmium, 12.9 mg of zinc and 26.2 mg of lead. Thus, the conducted investigations have shown that the yeast strain Rhodotorula rubra g2/1 simultaneously possesses high levels of resistance to copper and the ability to absorb this metal.