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

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.