真菌对重金属Pb(Ⅱ),Cd(Ⅱ),As(Ⅲ)和Cr(Ⅵ)耐受性的比较研究

Comparative Study on Pb(Ⅱ), Cd(Ⅱ), As(Ⅲ), Cr(Ⅵ) Resistance Characteristics of Fungus

从两种不同土壤环境中筛选获得19株真菌,并对其重金属耐受性进行比较分析。其中,从重金属污染严重的湖南水口山有色金属矿区土壤中筛选获得17株真菌,经鉴定分别属于曲霉属、木霉属、青霉属和镰孢属;从重金属污染较轻的廊坊经济开发区绿化用地中筛选获得2株真菌,经鉴定均为黑曲霉。研究重金属对不同土壤环境中分离的真菌的最小抑制浓度(MICs),分析菌种、生存环境、重金属浓度等因素对真菌重金属耐受性的影响,探讨真菌耐受高浓度重金属的机理。研究表明,从矿区分离获得的真菌中,Aspergillus niger PTN84等可耐受144 mmol/L Pb(Ⅱ),A.terreus PTN21,A.flavus PTN29和Trichoderma asperellum PTN1可耐受36 mmol/L Cd(Ⅱ),Fusarium sp.PTN12,A.terreus PTN21和T.asperellum PTN1可耐受36 mmol/L Cu(Ⅱ),Fusarium sp.PTN12可耐受72 mmol/L As(Ⅲ),整体上其重金属耐受能力高于文献报道的菌株,在重金属土壤修复方面具有潜在的应用价值。

19 fungus were isolated from two different soil environments and a comparative analysis of their heavy metal tolerance was conducted. Among them, 18 fungus, i.e. Aspergillus sp., Trichoderma sp., Penicillium sp., Fusarium sp., were isolated respectively from the contaminated soil of Shuikoushan nonferrous metals mine in Hunan Province; 2 fungus, identified as Aspergillus niger., were isolated from non-contaminated soil in green land located in Langfang Economic Development Zone. Fungus isolated from the contaminated soil and noncontaminated green land as well as those reported previously are compared in terms of their heavy metal resistance characterized with the minimal inhibitory concentrations（MICs）. As results, mechanism of fungal resistance of high concentrations of heavy metals was revealed. The fungus of heavy metal resistance primarily relies on the sites of their isolation, metal species, fungi species and metal speciation. Considering their high heavy-metal tolerance, e.g. MICs 144 mmol/L for Pb（Ⅱ）, 36 mmol/L for Cd（Ⅱ） and Cu（Ⅱ）, and 72 mmol/L for As（Ⅲ）, the isolated fungus perform excellent and thus have higher potential for soil restoration.