矿区重金属污染土壤中铅镉抗性细菌的筛选及其活化作用研究

Screening of bacteria resistant to heavy metal contaminated soil in cadmium-lead mining area and their effects on activation of cadmium-lead

从广西大新铅锌矿区重金属污染土壤中分离筛选出生长良好、产酸能力强的镉抗性菌株K1和铅抗性菌株K2,经革兰氏染色呈阴性,杆状菌体。菌株K1和K2的最适生长温度均为28℃,最适pH值为7和8。将菌株K1和K2分别接种到添加不溶性镉、铅的液体培养基(28℃培养48h)和含有固定态镉、铅的土壤(28℃培养5d)中,结果液体培养基中接菌处理比不接菌对照有效态镉、铅含量分别增加844.62%和370.48%,pH值分别降低2.95和2.07;土壤中接菌处理比不接菌对照有效态镉、铅含量分别增加42.42%、19.23%。说明两菌株具有较强的重金属镉、铅活化能力,可作为试验材料应用于抗性菌株强化植物富集重金属镉、铅研究中。

Two strains, viz., K1 （cadmium resistant） and K2 （lead resistant） have been isolated from heavy metal contaminated soil in Daxin lead-zinie mining area, Guangxi. The strains K1 and K2 grew we//, showed strong acid producing ability, negative in gram staining and had the baeuliform thallus. The optimum growth temperature and pH for strains K1 and K2 was 28℃ and 7 and 8, respectively. The suspension of activated strains K1 and K2 was inoculated and cultured in liquid culture medium containing insoluble Cd （100 mg/L） and Pb （100 mg/L） for 48 hours （28℃） and soil for fixing Cd and Pb for 5 days （28℃）, respectively. The results showed that the available Cd and Pb contents in culture medium were increased by 844.62 % （K1） and 370.48 % （K2） as compared with the control （no strain）, and the pH was decreased 2.95 （K1） and 1.89 （K2）. The available Cd and Pb content in soil inoculated with K1 were increased by 42.42% and 19.23%, respectively, compared with the control. Theses results indicated that two resistant bacteria strains had stronger activation effects on Cd and Pb, and could be used for the phytoremediation experiments in Cd and Pb toxic soils.