IN THIS STUDY, two isolates capable of biosorption of Cr(VI) were isolated from chromium rich effluent treatment plant located at Magra Al-Oyoon, Old Cairo, Egypt. The abundance of bacteria residing in tannery waste water with high metal content was studied. Seventy-two bacterial isolates were recovered by direct plating; two of them were resistant to high chromium concentration (up to 30 mmol chromate). According to the morphological, biochemical and the 16S rRNA sequence analysis they were identified as Bacillus tequilensis and Planococcus citreus .
The atomic adsorption spectroscopy showed that reduction of chromate content in the cell free supernatant was 59.8% and 45.8% for Bacillus tequilensis and Planococcus citreus, respectively, after 24 hr of incubation at 30°C. Moreover, both scanning electron micrographs and EDX analysis showed accumulation of chromate on both isolates. Bacillus tequilensis and Planococcus citreus had high potential for hexavalent chromium removal and can be used for detoxification of waste containing hexavalent chromium along with other heavy metals in media with high salt concentration.