安徽铜陵尾矿堆中三价砷抗性菌株的分离、鉴定及16S rDNA分析

从安徽铜陵杨山冲尾矿库采集表层尾矿样品,通过砷富集培养,从3份样品中筛选得到3株具有较强As(Ⅲ) 抗性的细菌 WK-21、WK-31 和 WK-32,用不同 NaAsO2 浓度的 LB 培养基对菌株进行砷抗性检测,结果这3株菌分别能耐受32、56和50 mmol/L的As(Ⅲ),具有较高的耐砷性.对这3株菌进行不同梯度浓度 As(Ⅲ) 环境中的生长规律研究,结果表明砷在低浓度时对细菌生长有轻微促进作用或者几乎没影响,但随着砷浓度增大,抑制作用明显增强.根据对这3株菌进行形态观察、生理生化鉴定以及16S rDNA序列比对分析,鉴定出这3株菌分别属于Arthrobacter sp.、Rhodococcus equi和Paenibacillus sp.菌属.由于这些菌株分离于尾矿库的尾矿堆中,因此,本文研究结果为进一步研究尾矿库金属污染的微生物修复及微生物抗金属机制提供了材料.

Isolation, identification and 16S rDNA sequences analysis of arsenic_resisting bacteria from mine tailing dumps of Tongling in Anhui Province

Three bacteria strains resistant to arsenic(Ⅲ), named WK-21, WK-31 and WK-32, were enriched with 2×10~3 mol/L NaAsO_2 and isolated on plates from the three pieces of rock (or soil) samples from Yangshanchong mine tailing dumps of Tonglin in Anhui Province. These strains are all aerobiotic and have a high resistance to arsenic(Ⅲ), and are respectively resistant to the most arsenic(Ⅲ) of 32, 56 and 50 mmol/L after being cultivated for 48 hours on the solid LB medium. Through a study of their growth in different concentrations of arsenic(Ⅲ), the authors found that the arsenic of low concentration made a small impact on or even slightly promoted the bacteria's growth and that, when the concentration of arsenic(Ⅲ) increased, the suppression of the growth was clearly enhanced. Based on a careful observation of the three strains' morphological characteristics, physiological and biochemical characteristics and 16S rDNA sequences, the authors identified the three strains as Arthrobacter sp., Rhodococcus equi and Paeni-bacillus sp., respectively. Since these arsenic-resisting strains were isolated from the soil samples of mine tailing dumps, the data obtained are likely to provide valuable materials for further studies of the environmental microbial remediation in the same kind of areas polluted by heavy metals and the mechanism for microbial resistance to heavy metals.