Enhancement of chromium removal from industrial effluent drain by Pseudomonas fluorescens SC106 and Bacillus subtilis SC106 consortia

Two bacterial strains capable to remove chromium (Cr VI) ions from tanneries effluent were isolated from contaminated soil in the present work and identified as Pseudomonas fluorescens SC106 and Bacillus subtilis SC106. The isolates are capable to remedy Cr (VI) as mono cultures and in consortia and their efficiencies were compared. Agarose gel analysis revealed that the resistance gene is a chromosomal gene in Pseudomonas fluorescens SC106 and a plasmid-borne gene in Bacillus subtilis SC106 (about 24 kb). The isolates were examined for their tolerance to hexavalent chromium and their ability to reduce Cr (VI) to Cr (III). Utilization of Cr (VI) reducing microbial consortium has enhanced the efficiency of the process of detoxification of Cr (VI) to Cr (III). The results indicate that the microbial consortia and the mono cultures of the above isolates can be useful for Cr (VI) detoxification of chromium contaminated environment. Before remediation, the chromium content of the effluent was 570 mgL(-1), after which, it reduced to 2.8 - 6.3 mgL(-1). The superlative removal activity was observed by immobilized beads consortia of P. fluorescens SC106 and B. subtilis SC106 (99.63%).