Isolation and identification of a chromium-resistant bacterium and its resistance to Cr(Ⅵ)
The chromium-tolerant bacteria were isolated and identified by macro-genetic sequencing,16SrDNA and construction of a phylogenetic tree from a chromium-containing farmland sample in Shandong Province,and their resistance to Cr(Ⅵ)was studied by scanning electron microscopy.In agricultural soils containing chromium,the main bacteria is Enterobacter cloacae,which is named Enterobacter cloacae SD.Cr(Ⅵ)tolerant concentrations of SD up to 3 200 mg/L.Under the cultivation conditions of 150 mg/L Cr(Ⅵ),the number of colonies is smaller and more dispersed than without Cr(Ⅵ),but the individual colonies are larger.The surface of SD cells is rough and appears to produce sediment.The strain SD can grow better with yeast infusion as carbon source,pH=7 and incubation temperature 30 ℃.The removal rate of Cr(Ⅵ)by SD is 39.67％at 150 mg/L Cr(Ⅵ).The result shows that Enterobacter cloacae SD can tolerate high concentrations of Cr(Ⅵ)while having a certain removal capacity for Cr(Ⅵ),which provides a possible strain resource for the microbial remediation of Cr(Ⅵ)contamination.
chromium-contaminatedisolation and identificationEnterobacter cloacaeCr(Ⅵ)microbial remediation
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