一株耐铅、锌、铬菌株的分离鉴定及其吸附能力

【背景】采矿带来的土壤重金属污染问题对生态环境和人类健康产生了极大的危害，因此矿区重金属污染问题亟待解决。生物修复法成本低、资源广、没有二次污染，是修复土壤重金属污染的有效途径。【目的】以山东省曲阜市某煤矸石山周围土壤为材料，采用平板划线法分离筛选一株同时对铅、锌、铬有高耐性且吸附能力强的菌株。【方法】通过形态学特征、生理生化鉴定、分子生物学方法鉴定菌种；采用原子吸收分光光度计测量各重金属的浓度。【结果】鉴定菌株为蜡状芽孢杆菌(Bacillus cereus)，命名为Bacillus cereus MZ-11。菌株MZ-11在pH为5.5?8.5、温度为15?45 °C、NaCl质量分数为2%?8%时可正常生长。菌株MZ-11最高耐铅、锌、铬浓度高达1 000、1 200、1 600 mg/L。在培养基中铅、锌、铬3种重金属浓度分别为初始浓度(含Pb2+、Zn2+、Cr6+浓度分别为50、60、80 mg/L)、初始浓度的5倍、10倍、20倍的条件下，MZ-11对Cr6+和Zn2+的吸附比例则随浓度的提高逐渐增大，吸附百分比均在98%?99%以上。对Pb2+的吸附比例有一个最高值，并且Pb2+的浓度为初始浓度的5倍时，MZ-11对Pb2+的吸附比例达最大值97.01%。【结论】菌株MZ-11对铅、锌、铬有高耐性和较好的吸附能力，为生物法修复矿区复合重金属污染和矿区生态环境提供了有力的理论支持。

Isolation, identification and adsorption capacity of a strain resistant to lead, zinc and chromium

Background] The problem of heavy metal pollution caused by mining has caused great harm to the ecological environment and human health. Therefore, the problem of heavy metal pollution in mining areas needs to be solved urgently. Biological remediation method has low cost, wide resources and no secondary pollution. It is an effective way to remediate soil heavy metal pollution. Objective] Using the soil around a coal gangue mountain in Qufu city, Shandong province as a material, a strain with high tolerance to lead, zinc, and chromium and strong adsorption capacity was separated and selected by the flat line method. Methods] Morphological characteristics, physiological and biochemical identification, and molecular biology methods were used to identify the strain. The concentration of each heavy metal was measured by an atomic absorption photometer. Results] The identified strain was Bacillus cereus, named Bacillus cereus MZ-11. The strain MZ-11 can grow normally when the pH was 5.5?8.5, the temperature was 15?45 °C, and the NaCl mass fraction was 2%?8%. The strain MZ-11 had the highest resistance to lead, zinc and chromium up to 1 000, 1 200 and 1 600 mg/L. The three heavy metal concentrations of lead, zinc, and chromium in the medium were the initial concentration (containing Pb2+, Zn2+, and Cr6+ at 50, 60, and 80 mg/L, respectively), and the initial concentration was 5 times, 10 times, and 20 times. As the concentration increased, the adsorption ratio of strain MZ-11 to Cr6+ and Zn2+ gradually increased, and the adsorption percentages were all above 98%?99%. Under the condition that the Pb2+ concentration was 5 times the initial concentration, the adsorption ratio of MZ-11 to Pb2+ reached the maximum 97.01%. Conclusion] Strain MZ-11 has high tolerance to lead, zinc and chromium and good adsorption capacity, which provides strong theoretical support for bioremediation of heavy metal pollution in the mining area and ecological environment of the mining area.