Copper ions uptake by T. farahensis in modified Neff’s medium containing different concentrations of metal ions at different time intervals. a, Maximum metal uptake was observed at 50 µg/ml stress level. At 100 µg/ml, there was a decrease in metal uptake, mainly due to decrease in viable count; b, In terms of metal uptake rate, a bimodal uptake of copper was observed at 5, 10 and 50 µg/ml copper ion concentration. The metal uptake rate was maximum during second quarter in the presence of lower (5 and 10 µg/ml) and during first quarter of first hour in the presence of higher (50 and 100 µg/ml) metal ion concentrations. The second cycle of metal uptake was initiated after 4 hours of copper addition. The metal uptake rate once decreased remained low in the case of 100 µg/ml metal concentration.