Isolation and Evaluation of the Tolerance of Industrial Wastewater Bacteria to Heavy Metals Toxicity

Abstract

In the present investigate, 123 bacterial isolates were isolated from different sources of industrial wastewater and polluted soil. These isolates were cultivated on different heavy metal ions (Ni+2, Zn+2, Fe+3, Al+3 and Cr+5) at different concentrations. Among these isolates, 100 bacterial isolates were heavy metal tolerance and 10 isolates were selected which gave the highest growth on 0.56, 7.00, 61.00, 61.00 and 2.20 ppm of Ni+2, Zn+2, Fe+3, Al+3 and Cr+5, respectively. Out of 10 isolates, 3 isolates namely C4, C6 and C12 were capable to grow (tolerated) at high concentrations of the tested metal ions and gave a high growth ranged from 1.02-1.29, 0.84-1.15 and 0.74-1.31 in presence of Ni (at 17.8 ppm), Zn (at 224.03 ppm) and Cr (at 70.4 ppm), respectively. Carbon and nitrogen sources influence were studied to optimize the growth of tolerance tested isolates on a high metal ions concentration. It was found that glucose followed by whey were the best one sole of carbon sources and beef extract and the mixture of beef extract and peptone were the best nitrogen sources for removal of Ni, Zn and Cr (at 70.4 ppm) by the tested isolates.