ISOLATION AND IDENTIFICATION OF A NEW SULFATE-REDUCING BACTERIUM AND ITS IN SITU REMEDIATION EFFECT OF HEXAVALENT CHROMIUM-CONTAMINATED SOIL
Microbial reduction of Cr(Ⅵ)to Cr(Ⅲ)is a promising method for remediation of chromium-contaminated soil.Molecular biology was used to identify the species of the strain,and the in situ remediation effect of hexavalent chromium was evaluated through laboratory tests and physical simulation experiments.The results showed that the 16S rDNA full-length sequence of the isolated strain capable of reducing Cr(Ⅵ)was analyzed in Ezbiocloud data,and the similarity was 98.89％with Desulfovibrio desulfuricans DSM 642T,named D.desulfuricans S-7.The most suitable growth temperature for D.desulfuricans S-7 was 30 ℃,while the most suitable pH was 7.0,and the suitable NaCl concentration was 0 to 10％.The results showed that the removal rate of 25 mg/L Cr(Ⅵ)was 79.74％,and the growth and reproduction of the strain was inhibited under an initial 100 mg/L of Cr(Ⅵ).The simulation experiment results revealed Cr(Ⅵ)concentration in the soil changed from 50.0 mg/kg to 3.1 mg/kg,and its removal rate reached 93.8％,while the remediated soil could meet China's national standard,GB 36600-2018,for Class 1 development land.This study showed that D.Desulfurians S-7 can effectively remediate Cr(Ⅵ)contaminated soil in anaerobic environment,providing a new alternative for in-situ remediation of deep-layer Cr(Ⅵ)contaminated soil.
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