Abstract:
Bioremediation of hexavalent chromium is an economically and
environmentally friendly approach. In this study three species of bacteria
Micrococcus variance, Pseudomonas aeruginosa and Bacillus circulance
which were previously isolated from chromium containing effluent, were
used to test their Cr(VI) removal efficiency. The removal percentages were
tested using 5, 10, 20, 30, 40 mg/L concentrations of Cr(VI) in tris minimal
medium. Diphenylcarbazide assay was used to determine the remaining
Cr(VI) concentrations by measuring absorbance at 540 nm wavelength
spectrophotometrically. According to results Bacillus circulans
demonstrated the highest removal percentages of 98.16%, 78.49 %,
35.67%, 17.06%, and 5.23% for the concentrations of 5, 10, 20, 30, and 40
mg/L of Cr(VI) respectively. Moderate removal percentages of 95.64%,
54.96%, 33.57%, 11.74% and 1.98% were shown, respectively by
Pseudomonas aeruginosa. The Lowest Cr(VI) removal percentages were
observed for Micrococcus variance with the values of 92.26%,45.72%,
27.69 %,8.38% and 0.3% respectively.
