Abstract

Heavy metals can cause disastrous effects on any living organisms. Probiotics have the ability to reduce metal toxicity. Bioremediation of polluted waters using these bacteria could be an alternative to conventional remediation methods. The aim of this study was to isolate and characterise heavy metal resistant probiotics. Soil samples were collected for isolation of probiotics. Morphological, biochemical and molecular characterisation were performed for the isolates. In addition, a preliminary heavy metal MIC test was done followed by AAS analysis. Four Enterococci (BT1, BT2, MC1 and MC2) and Bacillus acidiproducens (SM1 and SM2) were isolated. Moreover, all the isolates demonstrated probiotic characteristics. BT1 and BT2 were able to tolerate mercury, cadmium, lead and chromium but they demonstrated poor mercury-removal abilities (0.75 to 1.42%). MC1 and MC2 isolates could grow in medium supplemented with cadmium, lead and chromium respectively. MC1 showed the highest level of lead removal (43.00 ± 0.776%) and cadmium removal (46.19 ± 7.651%) from broth media. Yet, SM1 and SM2 isolates tolerated only lead and chromium. SM2 had the ability to remove the highest amount of chromium (43.06 ± 7.991%). These reasonable heavy metal removal abilities could be further studied for efficient use in bioremediation.

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