多粘芽孢杆菌(Paenibacillus polymyxa)吸附Cu^(2+)的实验研究  

Experimental Study on Adsorption of Cu^(2+) on Paenibacillus polymyxa

作　　者：丁雨[1] 陆现彩[1] 周跃飞[1] 陆建军[1] 王汝成[1] 

机构地区：[1]内生金属成矿机制研究国家重点实验室南京大学地球科学系,南京210093

出　　处：《高校地质学报》2007年第4期675-681,共7页Geological Journal of China Universities

基　　金：国家重点基础研究发展计划(2007CB815603);国家自然科学基金(40573001);博士点基金(20050284043;20050284044)资助成果

摘　　要：细菌表面往往存在多种化学基团,能够通过吸附作用影响环境流体中金属元素的活动性,从而与表生条件下的元素富集、矿物成核结晶等地球化学过程密不可分。为了深入认识细菌吸附作用的地球化学意义和环境效应,揭示细菌吸附金属离子的热力学行为,选择了多粘芽孢杆菌(Paenibacillus polymyxa)为研究细菌,系统开展了滴定实验和Cu2+吸附实验。通过连续酸滴定方法分析了细菌表面的化学特征,发现多粘芽孢杆菌在pH值为7.54~6.50范围内,表面带负电荷,表现出质子吸附行为;设计开展了Cu2+吸附实验,发现溶液的pH值对Cu2+吸附有一定影响,可能存在Cu2+与细菌表面质子的交换作用;根据Cu2+吸附等温线拟合计算,发现吸附等温线符合Langmuir和Freundlich吸附模型,根据Langmuir模型计算得到每个细胞的Cu2+饱和吸附量高达1.69×10-7mg。The microorganisms can clearly affect the mobility of metal ions in the environmental fluids because of abundant chemical groups on the cell surface. Adsorption of ions on the microorganism surface plays important roles in various biogeochemical processes, such as mineralization, nucleation and crystal growth. In order to disclose the adsorption mechanisms and to understand the adsorption capacity of bacteria, this paper experimentally studies the Cu^2＋ adsorption behavior of a widely occurring bacterium, Paenibacillus polymyxa. Firstly, consecutive acid titration was carried out. The results show that the range of optimum pH at which the Paenibacillus polymyxa absorbs H＋ is 7.54 - 6.00, and the surface of Paenibacillus polymyxa cell bears abundant negative charges, which, determines the ion adsorption capacity. Then, the CuE＋ adsorption isotherm of Paenibacillus polymyxa was measured. As the solution pH increases linearly with the increasing Cu adsorption capacity, it is deduced that the ion exchange between surface H^＋ and Cu^2＋ may be the potential mechanism of the apparent adsorption. The data fitting indicates that the biosorption process agrees well with both the Langmuir model and Freundlich model. According to the isotherm equation of Langmuir model, the calculated adsorption capacity of Cu^2＋ is as high as 1.69 ×10^-7 mg/cell.

关 键 词：多粘芽孢杆菌(Paenibacillus polymyxa) CU^2+ 吸附 吸附模型 

分 类 号：Q939.99[生物学—微生物学]