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研究报告

Isolation, identification and Pb(Ⅱ) biosorption characterization of a lead-resistant strain

摘要：从某铅矿区土壤中筛选出一株耐铅细菌,对其进行初步鉴定,并对Pb²⁺吸附特性和机理进行研究.16S rDNA 序列相似性分析表明,该菌属于节杆菌属,将其命名为 Arthrobacter scleromae LY-1.菌株最大耐Pb²⁺浓度为500 mg·L^-1,此外,菌株对Zn²⁺、Cu²⁺、Ni²⁺、Co²⁺ 等重金属也有一定的耐受性.在初始Pb²⁺浓度为100 mg·L^-1、投菌量(鲜重)为10 g·L^-1、pH为6.0、温度为30℃、吸附时间为25 min时,吸附Pb²⁺效果较好,此时吸附率为99.61%,吸附容量为9.96 mg·g^-1,吸附等温方程符合Langmuir模型.透射电镜观察和红外光谱分析显示,菌株LY-1对Pb²⁺的吸附主要是细胞表面的吸附,菌体细胞表面的多种活性基团与Pb²⁺发生络合作用.

Abstract：A lead resistant bacterium was isolated from heavy metal-contaminated soil in a lead-zinc mining area. The bacterium was preliminarily identified and its Pb²⁺ removal characteristics were analyzed. The 16S rDNA sequence analysis revealed that this bacterium belongs to Arthrobacter sp. and was named as A. scleromae LY-1. Strain A. scleromae LY-1 possesses the capability of Pb²⁺ resistance up to 500 mg·L^-1 in aqueous solution. In addition, it also has certain resistance to other heavy metals such as Zn²⁺, Cu²⁺, Ni²⁺ and Co²⁺. Optimum conditions for maximum biosportion were found at pH of 6.0 with inoculation quantity of 10 g·L^-1 (fresh weight), initial Pb²⁺ concentration of 100 mg·L^-1, and contact time of 25 min at 30℃. Under such conditions, the adsorption rate and capacity reached 99.61% and 9.96 mg·g^-1, respectively. Efficient performance of the biosorbent is in accordance with Langmuir isotherm model. Transmission electron microscope (TEM) coupled with Fourier Transform InfraRed (FT-IR) results revealed that the biosorption process mainly happens on the surface of LY-1 cell and many active groups on the extracellular matrix can chelate the lead ions.