一株Cr(Ⅵ)还原菌的筛选鉴定及其还原特性研究

Isolation, Identification and Cr(Ⅵ)-Reducing Capacity of a Cr(Ⅵ)-Reducing Strain Enterobacterhormaechei

从山西某铬渣堆场土壤中分离得到一株能还原Cr(Ⅵ)的细菌C2L,通过形态特征、生理生化反应和分子生物学鉴定确定该菌株为霍氏肠杆菌(Enterobacterhormaechei)。该菌株能在较宽的p H值(5~9)和温度(25~45℃)范围内还原Cr(Ⅵ),最佳反应条件为p H8和30℃。在Cr(Ⅵ)初始浓度为50、100、200、400、800 mg·L-1时,C2L菌株对Cr(Ⅵ)的还原效率分别为99.3%、94.2%、85.6%、82.1%、58.2%。实验结果表明,该菌株在高Cr(Ⅵ)浓度下仍可表现出良好的还原能力,具有独特的还原Cr(Ⅵ)性能,在处理Cr(Ⅵ)污染土壤中存在极大的应用潜力。

Hexavalent chromium Cr(Ⅵ)is a highly toxic and mobile metal species. Reducing Cr(Ⅵ)to Cr(Ⅲ)has been considered to be one of remediation techniques for Cr(Ⅵ)-polluted water or soil. Here one Cr(Ⅵ)-reducing bacterial strain, C2 L, was isolated from a Cr(Ⅵ)-polluted soil in Shanxi Province. The strain was identified as Enterobacterhormaechei according to its morphological characteristics,physiological and biochemical reactions, and 16 S r DNA sequence analysis. To our knowledge, this is the first report on Cr(Ⅵ)reduction by Enterobacterhormaechei bacterial strain. The reduction of Cr(Ⅵ)occurred over a wide range of p H(5~9)and temperature(25~45 ℃)with the optimum performance at p H 8 and 30 ℃. At the initial Cr(Ⅵ)concentrations of 50 mg·L-1, 100 mg·L-1, 200 mg·L-1, 400 mg·L-1 and800 mg·L-1, the reduction rates of Cr(Ⅵ)by the C2 L strain were 99.3%, 94.2%, 85.6%, 82.1%, and 58.2%, respectively. The strain exhibited Cr(Ⅵ) reduction even at high Cr(Ⅵ) concentrations, suggesting that the strain possessed distinct capability for the Cr(Ⅵ)removal. This strain shows great potential to remediate Cr(Ⅵ)-polluted soils.