Copper Bioremediation Ability of Ciliate Paramecium multimicronucleatum Isolated from Industrial Wastewater

Abstract

The growing problems of environmental damage have been caused by the continuous outrush of heavy metals from industrial wastewater. To resolve this issue, bioremediation is playing a safe and eco-friendly role in the removal of these heavy metals from environmental wastewater bodies. It has provoked demand with regard to understanding the mechanisms of bioaccumulation and detoxification developed by the organisms living in the heavy metal-exposed industrial wastewater. The present investigation focuses on Paramecium multimicronucleatum, a ciliated protozoan isolated from industrial wastewater, with the objective of assessing its capabilities as an environmental bioremediator. Purified cell culture was maintained in bold basal salt medium and optimum growth conditions were determined. A maximum growth rate of 6.0–9.0 × 103 cells/mL at 25–30 °C and pH 7.0 was observed, and therefore revealed to be the optimal growth conditions for this species. It can tolerate 40–50 µg/mL of copper ion stress with little effect on growth rate as compared to control. It is able to uptake more than 80% of copper ions from the medium in 96 h. A significant twofold rise in glutathione content and non-protein thiols was recorded as an indication of a defensive mechanism in place to fight against the oxidative stress caused by the copper treatment. A notable increase of 50–70 µg/mL in total protein content of stressed cells in comparison to non-stressed was also observed as potential induction of some particular proteins for the purpose of resistance against copper stress.