Effect of copper on phosphate metabolism and 14co2-incorporation in free and immobilized cells of nostoc calcicola

The phosphate uptake, ATPase activities and 14CO2-incorporation were investigated in free living and immobilized cells of Nostoc calcicola under copper stress conditions. The maximum Cu concentration in free and immobilized N. calcicola cells was 60µM at which the immobilized cells were characterized by a faster rate of phosphate uptake than free cells. Immobilization was associated with decrease in vivo activities of ATPase(s), suggesting that the immobilized cells maintain sufficient ATP pool. 14CO2-incorporation in immobilized cells was less sensitive to Cu and degree of inhibition was less marked compared to free living cells. The tolerance of immobilized cells in terms of all the activities studied over free cells suggested that such a system could be successfully applied to remove heavy metals from polluted water through repeated cycles with no loss of cells in bioremediation.