Bioremediation of heavy metals using a novel species of ciliate Paramecium multimicronucleatum isolated from industrial wastewater

The introduction of heavy metals by industries in the aquatic ecosystem is a threatening alarm for living organisms. Bioremediation is an eco-friendly and inexpensive technique as an alternative to chemical methods for wastewater treatment. Wastewater samples were collected from ponds receiving effluents from the Kot Lakhpat Industrial zone, Lahore (Pakistan). Heavy metal-resistant ciliate, Paramecium multimicronucleatum was isolated and characterized with the help of 18SrRNA biomarker. The ciliate showed optimum growth at 25 °C ± 1 °C and pH 7. Growth patterns of P. multimicronucleatum were observed with and without metal stress in wheat grain medium. The minimum inhibitory concentration of cadmium, copper, zinc, and lead was 60, 70, 110, and 160 μg ml−1, respectively. The maximum uptake by Paramecia for Cd, Cu, and Zn was recorded as 90%, 82%, and 93% respectively after 96 h of exposure in each case. While 90% of lead ions were absorbed by Paramecium cells after 48 h of exposure. The order of uptake ability by Paramecium sp. was Zn2+ > Cd2+ > Cu2+ > Pb2+. This preliminary study of exploring bioremediation ability of this ciliate would be helpful for investigating it further using advanced molecular techniques.