Isolation, identification and biosorption characteristics of a lead and cadmium resistant fungus

Abstract:

[Objective] A lead and cadmium resistant strain was isolated from the polluted soil of Zhalong wetland, and the influences on lead and cadmium adsorption under different conditions are discussed. [Methods] The streak plate method and progressive domestication were used for screening lead and cadmium resistant strain. The strain was identified by physiological and biochemical tests, and by ITS sequence analysis. The optimal condition of the lead and cadmium resistant strain was explored, and Langmuir and Freundlich isothermal adsorption models were used. [Results] A lead and cadmium resistant strain JB15 was isolated as Beauveria bassiana, and the maximum tolerant Pb²⁺ and Cd²⁺ concentration of the strain was 1200 mg/L and 200 mg/L, respectively. Optimum conditions for adsorption were found at pH of 7.0 with inoculation quantity of 8.0 g/L, at 30℃ for 60 min. Under such conditions, the lead and cadmium adsorption rate reached 52.27% and 62.38%, and the lead and cadmium adsorption capacity reached 19.60 mg/g and 3.98 mg/g, respectively. The adsorption process of the strain was fitted well on Langmuir adsorption isotherm model. [Conclusion] The isolated strain JB15 has a good adsorption effect and provides theoretical foundation for microbial remediation of soil heavy metal contamination.