Isolation and Characterization of Lead Tolerance Bacteria Collected from Different Mining Site in Minna, Niger State

Abstract

Hassan Mohammed*

Lead released from mining site into the environment has caused serious environmental pollution thereby threatening human and animal lives. Hence this study focus on characterization of lead tolerance bacteria isolated from lead contaminated soil of different mining site in Minna, Niger State. Isolation was carried out using Nutrient agar and MacConkey agar. Tolerance test was done using Nutrient Agar containing lead acetate at different concentrations ranging from 0.1-1.0mg/ml. The ability of the isolate to utilize lead was tested using agar-agar at different concentration ranging from 0.2-0.5mg/ml of lead acetate. Degradation potential of the isolates was determined using peptone water containing 0.06mg/ml lead acetate; absorbance was taken using Jenway 6320D spectrophotometer at 600nm for seven days at interval 24hhrs. The isolates were identified by morphological and biochemical tests. Few bacteria colonies were observed on both nutrient agar and MacConkey agar. The bacteria isolates sub cultured; HM1, HM2, HM3, and HM4 were identified as Staphylococcus aureus, Bacillus cereus, and Micrococcus letus. From the tolerance result, all the isolates were able to tolerate lead at 0.1mg/ml. For utilization test, all the bacteria isolates zone of inhibition increases as the concentration increases with Staphylococcus aureus having the highest zone of inhibition of 26.22. The cumulative percentage of degradation on the 7th day for Staphylococcus aureus, Bacillus cereus, and micrococcus letus are 32.81%, 29.15%, 26.0% and 27.84% respectively. These bacteria can be utilized as potential bioremediation agent to reduce lead pollutant in environment.