The aim of this study was to isolate and identify heavy metals resistant probiotics, mainly lactic acid bacteria, from three different metal-polluted soils in Mauritius and to assess their ability to remediate/remove specific heavy metals, namely cadmium, chromium, lead and mercury from aquatic environment.
Soils samples were collected for isolation of probiotics. Morphological, biochemical and molecular characterisation were performed. 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.
All the isolates were acid and bile tolerant and produced lactic acid by metabolizing glucose. Moreover, the six bacteria have moderately hydrophobic cell wall and showed similar antibiotic susceptibility profiles. However, no antibacterial activity was observed.
BT1 and BT2 were able to tolerate mercury, cadmium, lead and chromium. MC1 and MC2 isolates could grow in MRS medium supplemented with cadmium, lead and chromium. Yet, SM1 and SM2 isolates tolerated only lead and chromium. Finally, all the isolates showed reasonable removal efficiency of the heavy metals.
Key words: Bioremediation, probiotics, heavy metals, Enterococcus, Bacillus acidiproducens
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