1株抗重金属铬细菌的分离、鉴定及抗性基因型的初步研究

Isolation,Identification and Genotypic Analysis of a Bacterium Strain With Resistance to Chromium(Ⅵ)

从湖北省某重金属矿区土壤中分离到1株抗Cr6+(Ⅵ)的菌株,命名为MDS07。该菌株可以在含12mmol/L的Cr6+(Ⅵ)培养基上正常生长。经对该菌株进行形态观察和16S rDNA序列比对分析,确认该菌株为巨大芽孢杆菌Bacillus megaterium。通过构建系统发育树,分析了该菌在系统发育中的地位。对MDS07进行了重金属抗性谱研究,结果表明该菌株对Cr、Zn、Ni等重金属具有较高的抗性。进一步研究发现,MDS07菌株同时含有chrB、czcD和nccA等基因,它们分别具有Cr、Zn、Ni等重金属抗性,表明MDS07菌株的重金属抗性是由抗性基因引起的。

A bacterium strain resistant to chromium （Ⅵ）, named MDS07, was isolated from soil of heavy metal pollution in Hubei Province. It can resist 12 mmol/L chromium （Ⅵ）. The strain was identified as Bacillus megaterium based on morphology and the phylogenic analysis of the 16S rDNA sequence. Strain MDS07 was highly resistant to Zn,Cr and Ni. The chrB,czcD and nccA genes responsible for resistance to Cr, Zn, and Ni, respectively, were shown to be present in strain MDS07 via RCR amplification.