Heavy metal tolerance in the psychrotolerantCryptococcussp. isolated from deep-sea sediments of the Central Indian Basin
Deep-sea isolate of the psychrotolerant yeast Cryptococcus sp. (NIOCC #PY13) obtained from polymetallic nodule-bearing sediments of the Central Indian Basin was examined for its capacity to grow in the presence of various concentrations of the heavy metal salts i.e. ZnSO 4 , CuSO 4 , Pb(CH 3 COO) 2 and CdCl 2 . It demonstrated considerable growth in the presence of 100 mg l -1 concentration of the above mentioned four heavy metal salts both at 30 as well as 15˚C. Optimum pH for growth of this
... olate ranged from 6 to 8 in the presence of heavy metal salts at these two temperatures. Scanning electron microscopic (SEM) studies exhibited altered cell surface morphology of the cells under the influence of heavy metals compared to that with control. The adsorption of heavy metals to the cells was demonstrated by FTIR and EDAX analysis. As evidenced by atomic absorption spectrophotometric (AAS) analysis, about 30-90% the heavy metals were removed from the culture supernatant after 4 days of growth at 30˚C. This deep-sea yeast isolate appears to be a potential candidate for bioremediation of metal contaminated sites. Moreover, its metal tolerance properties provide a significant insight on its ecological role and adaptations to grow in such extreme conditions.