Chromium (VI) contamination has accelerated due to rapid industrialization worldwide. Aim of this study is to check the bacterial species for their tolerance towards chromium (VI), chromium (VI) reduction under various pH and further check whether these bacteria are reducing Cr (VI) under the influence of various metals, carbon source and protein denaturant. Bacterial strains were isolated from metal contaminated soils of Abeokuta. All of the isolates showed tolerance to chromium (VI). Among all the strains, only Klebsiella spp. PB6 showed reduction of chromium (VI). Maximum reduction (89.5%) of chromium (VI) was observed at pH 7 by Klebsiella spp. PB6. Similarly, Klebsiella spp. PB6 also reduced the chromium considerably at pH 6 (88%) and pH 8 (71%) at a concentration of 100 μg Cr mLG 1 after 120 h of incubation. Klebsiella spp. PB6 also showed chromium (VI) reduction under various metals, protein denaturant and carbon source. There was maximum decrease in Cr (VI) reduction under the influence of ZnCl 2 which was followed by PbCl 2. Urea and citrate also decreased Cr (VI) reduction compared to control cells. Due to above properties strains could therefore be used as bioremediators of metals in soils contaminated with heavy metals.

Chromium (VI) contamination has accelerated due to rapid industrialization worldwide. Aim of this study is to check the bacterial species for their tolerance towards chromium (VI), chromium (VI) reduction under various pH and further check whether these bacteria are reducing Cr (VI) und er the influence of various metals, carbon source and protein denaturant. Bacterial strains were isolated from metal contaminated soils of Abeokuta. All of the isolates showed tolerance to chromium (VI). Among all the strains, only Bacillus species PB5 showed reduction of Chromium (VI). Maximum reduction (90%) of chromium (VI) was observed at pH 7 by Bacillus species PB5. Similarly, Bacillus species PB5 also reduced the chromium considerably at pH 6 (86%) and pH 8 (87.5%) at a concentration of 100 μg Cr mLG 1 after 120 h of incubation. Bacillus species PB5 also showed chromium (VI) reduction under various metals, protein denaturant and carbon source. There was maximum decrease in Cr (VI) reduction under the influence of PbCl 2 which was followed by ZnCl 2. Urea and citrate also decreased Cr (VI) reduction compared to control cells. Due to above properties strains could therefore be used as bioremediators of metals in soils contaminated with heavy metals.