Immobilization of cesium-resistant bacterial cells by radiation polymerization and their bioremoval efficiency

Abstract

Biological approaches for the removal of heavy metals and radionuclides from contaminated water are reported. The present study was carried out with the objective of identifying bacterial strains for the uptake of cesium that could be used for bioremediation. Polymer carriers prepared by radiation polymerization were used for the immobilization of bacteria and the efficiency of free cells and immobilized cells for the removal of cesium was evaluated. Thirty-five bacterial isolates were screened for resistance to cesium and five bacterial isolates based on resistance to cesium (BR-3, BR-6, BR-21, BR-39, BR-40) were selected for immobilization. Polymer carriers were prepared using 10, 20, 30, 40 and 50% acrylamide at different doses of 1 to 5 kGy gamma radiation. The polymer carriers prepared using 30% and 40% acrylamide at 5 kGy were found to be suitable based on gel fraction and absorption capacity for the immobilization of bacterial cells. Bioremoval of cesium by free and immobilized bacterial cells was evaluated. Significant reductions of 76–81% cesium were observed with bacterial cells immobilized by radiation polymerization.