Chromium-resistant bacteria screening, identification and remediation of chromium contaminated soil

Six bacteria were isolated from the chromium contaminated soil, named STU1, STU2, STU3, STU4, STU5, STU6. The former three belong to the Monas as indicated by morphological, physiological and biochemical experiments and 16SrDNA sequence analysis and phylogenetic analysis. The homology of STU1, STU2, STU3 with Pseudomonas Stutzeri were 99.92%, 100% and 99.92% respectively, the homology of STU6 with Brevundimonas diminuta was 99.77% and the homology of STU4 and STU5 with achromobacter sp. were 100%. The results of the study, which using these bacteria to remediate the comtaminated soil by added chromium (VI), show that the adding of the advantageous remediation bacteria to the soil can increase the capability for reducing concentration of chromium (VI). The removal rate is 60-99.5% while only adding bacteria liquid to oligotrophic chromium (VI ) polluted soil. And the removal rate is 92-99.6% while adding eutrophy bacteria liquid to nutrient-rich chromium (VI) contaminated soil. The optimum pH of remediation bacteria liquid is 7.5, and the optimum temperature is 30 °C;. To add cattle dung can increase the remediation effect for chromium (VI) significantly.