一株耐锌真菌CTB430-1分离鉴定及其富集特性

从某锌尾砂坝土壤中筛选分离、纯化得到一株对锌具有较强抗性的菌株,命名为CTB430-1.对菌株进行形态观察、生理生化试验,采用ITS基因序列分析并构建系统发育树,鉴定该菌为黄曲霉（Aspergillus flavus）.研究其对Zn（Ⅱ）抗性和富集特性.结果表明：Zn（Ⅱ）对该菌株的最低抑菌浓度为800 mg/L;菌株对Zn（Ⅱ）的富集量在250 mg/L时达到最大,为40.37 mg/g;采用扫描和透射电镜观察富集前后菌丝体表面形态和内部结构变化,表明Zn（Ⅱ）毒害作用可能导致生长中菌丝表面结构破坏,CTB430-1富集Zn（Ⅱ）由表面吸附和胞内富集两部分组成.

Isolation of Zinc-resistant Fungus CTB430-1 and Its Bioaccumulation Characteristics

A strain of resistance to zinc with high concentration,named CTB430-1,was isolated from the metal-polluted sediment of soils at a zinc tailing.The strain was identified by analyzing the morphology and measuring the ITS sequence.A phylogenetic tree was constructed with the published ITS sequences of relative fungus species.In the phylogenetic tree,the CTB430-1 strain has the closest relation to Aspergillus flavus with 99％ sequence homology,and it was characterized as Aspergillusflavus.The minimal inhibitory concentration of Zn（Ⅱ） for CTB430-1 growth was 800 mg/L,and the maximum bioaccumulation capacities of Zn（Ⅱ） was 40.37 mg/g at initial concentration of 250 mg/L.Furthermore,the changes of surface morphology and internal structure of strain CTB430-1 were obtained by scanning electron micrograph and transmission electron microscope.This suggested that the surface structure of mycelium might be destroyed by the heavy metal toxicity,and the bioaccumulation of CTB430-1 included extracellular and intracellular biosorption.