Isolation of Cr(VI) Resistant Bacteria and Exploration of Cr(VI) Removal Mechanism of Strain n-9

8 Cr(VI) removing strains were obtained from 24 Cr(VI) resistance bacteria isolates. 6 strains showed more than 50% removal rates for 50 mg/L of Cr(VI) and 5 strains exhibited more than 50% removal rates for 80 mg/L of Cr(VI). Strains n-1, n-6, n-9 and n-12 could remove Cr(VI) more efficient at lower Cr(VI) concentration, while strains n-7, z-2, z-3 and z-7 could remove Cr(VI) at higher concentration. In which, strain n-9 could complete remove Cr(VI) by cultured in TYG broth containing 50 mg/L Cr (W) at 28 degrees C for 3 days and remove 80.7% of it in 80 mg/L Cr (VI). Further exploration indicated that strain n-9 could reduce Cr(VI) by endoenzyme related to NADPH, which was carried out by comparing the removal ability of living cells, culture supernatant, inactived cells, cell lysate solution and the effect of SDS, thermal treatment, as well as the oxidoreductase coenzyme NADPH.