煤矿区耐镉青霉菌的分离鉴定

Isolation and characterization of cadmium-resistant Penicillium sp. from coal mining area

摘要:

【目的】分离鉴定煤矸石中耐Cd2+菌株。【方法】用菌落形态和18S rRNA序列分析鉴定菌株, 研究菌株的重金属耐性和在酸性煤矸石浸出液的生长能力, 分析其抗氧化酶活性对重金属复合污染的响应。【结果】BJKD4菌株为青霉属(Penicillium sp.)菌, 能耐29 mmol/L的Cd2+, 不同重金属对BJKD4的毒性大小依次为: Cu2+>Ni2+>Cd2+>Pb2+或Zn2+>Mn2+。正交试验表明BJKD4菌株能在不同浓度重金属Cd、Zn、Ni和Mn等复合污染条件下生长, SOD活性在重金属复合污染时升高, CAT活性变化依重金属的种类和浓度不同而不同; 此外, BJKD4能在含有煤矸石酸性浸出液的培养基中生长, 并提高其pH。【结论】BJKD4菌株能耐多种重金属, 具有阻止煤矸石山淋溶液酸化的应用潜力。抗氧化酶在减缓重金属诱导的氧化胁迫中起重要作用。

Abstract:

[Objective] We isolated cadmium-resistant fungi from gangue pile of coal area and characterized their heavy-metal resistance. [Methods] The strain was identified by the morphological properties and 18S rDNA sequence homology analysis. Heavy-metal tolerance and the growth in acid leaching liquid of coal gangue were evaluated. The antioxidant enzyme activity of SOD (superoxide dismutase) and CAT (catalase) was assayed under mixed heavy-metals stress. [Results] The BJKD4 strain is the genus Penicillium sp. and could tolerate up to 29 mmol/L Cd2+, the optimum pH is 4.0?9.0. The order of heavy-metal toxicity to BJKD4 growth is: Cu2+>Ni2+>Cd2+>Pb2+ or Zn2+>Mn2+. Orthogonal experiment indicated that BJKD4 strain could survive in the medium containing different concentrations of a variety of heavy-metal ions, such as Cd2+, Zn2+, Ni2+ and Mn2+. SOD activity of BJKD4 is increased in response to heavy-metals, while the activity of CAT depended on the species and concentration of heavy-metal. Furthermore, BJKD4 could grow in medium containing an acidic leaching solution of coal gangue at alkali pH. [Conclusion] BJKD4 strain is tolerant to various heavy-metals and has the potential to prevent acidification of the gangue hill leachate, the antioxidant enzyme plays important role in alleviating the oxidative stress induced by heavy-metal ions.