In this research work, a locally isolated strains of Pseudomonas sp., and consortium of bacteria is used to reduce toxic hexavalent chromium to less toxic trivalent chromium at concentrations of 100, 200, 300 and 400 mg/L, respectively at pH 7 and temperature 30° C. Even though increasing the concentration of Cr (VI) in the medium decreased the growth rate showing the detrimental effect of this heavy metal, it could not be directly correlated with the amount of Cr (VI) reduced. The consortium of bacteria showed higher rate of reduction in 300 mg/L with overall reduction of 90.41% but the Pseudomonas sp., could show reduction up to 90% in the 100 mg I"1 initial concentration of hexavalent chromium only. High Cr (VI) concentration resistance and high Cr (VI) reducing ability of the analyzed strains make them suitable for additional studies related to bioremediation of hexavalent chromium.
Key words: Bioremediation, Pseudomonas, Chromium removal, Consortium of microbes