The characteristics of cadmium adsorption by Cd-resisting Kluyveromyces marxianus YS-K1

The characteristics of cadmium adsorption by Kluyveromyces marxianus YS-K1,a Cd-resisting yeast isolated from polluted soil,were studied.The results showed that Kluyveromyces marxianus YS-K1 had high resistance and effectual adsorption to cadmium.Even under cadmium concentration of 140mg/L it could grow up well.Under concentration below 30mg/L,the strain could also adsorb more than 90% of the cadmium in 24 hour incubation under the optimal pH value of 6.0 and the optimal temperature of 30℃.76% of adsorbed cadmium was concentrated on cell wall,9% on membrane and 15% in cytoplasm.The cadmium adsorption reduced 15% and 22% under the treatment of metabolic inhibitors DNP and DCC.Zinc not only competed with cadmium for cell surface binding sites,and reduced biosorption ability of Kluyveromyces marxianus YS-K1 to cadmium,but also competed in occupying the binding sites of entrance passageway of the cells,reducing bioaccumulation of cadmium,and recovering the inhibition activity of cadmium to the strain.