STUDY OF METAL TOLERANCE COLIFORM BACTERIA IN THE GOMTI RIVER WATER OF NORTHERN INDIA
This study was carried out to assess the incidence of metal resistance among coliform bacteria in terms of their viable count (cfu/ml) and minimum inhibitory concentrations (MIC) from the Gomti river water. It was investigated in heavy metal amended Nutrient Agar and Mac Conkey plates at varying concentrations 50 ‒ 800 and 100 ‒ 2000 μg/ml respectively. The results demonstrated that the growth and MIC of coliform were dependent upon the metals type and concentrations level. Reduction in coliform population is evident as metal concentration increased. Minimum MIC level was observed between 50-100 μg/ml against Cr6+ and maximum at between 1600-2000 μg/ml against Cd+, Ni+ and Hg2+ among isolates. Furthermore, increased levels of heavy metal concentration as well as thermotolerant coliforms were found from site A to C in heavy metal resistant (HMR) strains. The isolation rate of heavy metal coliforms strains was highest during the summer and monsoon months. Abbreviations: Minimum inhibitory concentration, MIC; Mercury, Hg2+; Cromium, Cr6+; Cadmium, Cd+; Nickel, Ni+; Copper, Cu2+; Cobalt, Co+; Zinc, Zn2+; Colony form unit, cfu; Heavy metal resistant, HMR.
5 , 2 , 2015
68 - 74