嗜酸氧化亚铁硫杆菌胞外聚合物与Cd~(2+)在吸附过程中的交互作用
|
摘要
从粤北大宝山酸性矿山废水(AMD)分离出具有较强耐镉活性的嗜酸氧化亚铁硫杆菌(Af菌),采用原子吸收分光光度技术和荧光光谱分析技术,研究Af菌胞外聚合物(EPS)与水中Cd~(2+)在吸附过程中的交互作用机制。分离获取的Af耐镉菌株最大耐受浓度为0. 03～0. 04 mol/L,表现出较强的耐镉活性;在Cd~(2+)的胁迫下,Af菌可通过产生EPS来抵御和去除Cd~(2+)的不利影响;当EPS吸附Cd~(2+)后,其类蛋白荧光峰强度增强,且在λ_(Em)=402 nm处产生一个新的宽大的荧光峰,并显示出较强的荧光强度。结果表明,Cd~(2+)与EPS间相互作用机制是电中和和离子架桥效应的协同过程,Cd~(2+)通过改变EPS表面电位和类蛋白疏水作用来介导EPS构象和絮凝体结构变化,进而促进EPS絮凝体的聚集,提高其絮凝效率和沉降性能。
A strain of Acidithiobacillus ferrooxidans( A f) was isolated from the acid mine drainage of Dabaoshan Mine in North Guangdong and showed a strong cadmium resistance. The atomic absorption spectrophotometry and fluorescent spectrophotometry technique were used to explore the interaction between extracellular polymeric substances( EPS) of A f. and Cd~(2+)during the adsorption. The maximal tolerable concentration of A f. to Cd~(2+)ranged from 0. 03 to 0. 04 mol·L~(-1) and showed a strong cadmium resistance. Under the stress of Cd,A f. could defend against Cd and decrease the harmful effect by producing and secreting EPS. After Cd~(2+)was adsorbed onto the EPS,protein-like fluorescence intensities strengthened,and a new wide fluorescence spectral peak located at402 nm appeared and showed great fluorescence intensity. The results indicated that the interaction between EPS of A f. and Cd~(2+)was one kind of collaborative process including charge neutralization and ion bridging effect. Cd~(2+)could change the conformation of EPS and had an impact on structure of floc by the effect of surface potential of EPS and hydrophobic interaction of protein-like,which promoted the accumulation of the EPS floc and improved the efficiency of flocculation and settling performance.
A strain of Acidithiobacillus ferrooxidans( A f) was isolated from the acid mine drainage of Dabaoshan Mine in North Guangdong and showed a strong cadmium resistance. The atomic absorption spectrophotometry and fluorescent spectrophotometry technique were used to explore the interaction between extracellular polymeric substances( EPS) of A f. and Cd~(2+)during the adsorption. The maximal tolerable concentration of A f. to Cd~(2+)ranged from 0. 03 to 0. 04 mol·L~(-1) and showed a strong cadmium resistance. Under the stress of Cd,A f. could defend against Cd and decrease the harmful effect by producing and secreting EPS. After Cd~(2+)was adsorbed onto the EPS,protein-like fluorescence intensities strengthened,and a new wide fluorescence spectral peak located at402 nm appeared and showed great fluorescence intensity. The results indicated that the interaction between EPS of A f. and Cd~(2+)was one kind of collaborative process including charge neutralization and ion bridging effect. Cd~(2+)could change the conformation of EPS and had an impact on structure of floc by the effect of surface potential of EPS and hydrophobic interaction of protein-like,which promoted the accumulation of the EPS floc and improved the efficiency of flocculation and settling performance.
引文
[1]周建民,党志,蔡美芳,等.大宝山矿区污染水体中重金属的形态分布及迁移转化[J].环境科学研究,2005,18(3):5-10.
[2]魏焕鹏,党志,易筱筠,等.大宝山矿区水体和沉积物中重金属的污染评价[J].环境工程学报,2011,5(9):1943
[3]陈美标,郭建华,姚青,等.大宝山矿区耐Cd2+细菌的分离鉴定及其生物学特性[J].微生物学通报,2012,39(12):1720-1733.
[4]聂国朝.胞外聚合物(EPS)在藻菌生物膜去除污水中Cd的作用[J].中南民族大学学报(自然科学版),2003,22(4):16-19.
[5]李生琳.分析化学实验[M].天津:南开大学出版社,1987:73-77.
[6]张倩,李孟,王弘宇,等.反硝化除磷菌胞外聚合物的提取及除磷研究[J].武汉理工大学学报,2013,35(2):130-133.
[7]高景峰,郭建秋,陈冉妮,等.三维荧光光谱结合化学分析评价胞外多聚物的提取方法[J].环境化学,2008,27(5):662-668.
[8]邹志辉,郑凯,谭志钊,等.胞外多聚物在嗜酸氧化亚铁硫杆菌吸附Mn2+、Ni2+、Pb2+中的作用[J].环境化学,2015,34(12):2263-2267.
[9]康福星,龙健,潘响亮,等.镉对松散和紧密胞外聚合物类蛋白的荧光滴定[J].环境科学学报,2009,29(2):360-366.
[10] Bi,S. Y.,Yan,L. L.,Pang,B.,et al. Investigation of three flavonoids binding to bovine serum albumin using molecular fluorescence technique[J]. Journal of Luminescence,2012,132(1):132-140.
[11]乐薇,吴小霞.荧光法研究芦丁-Zn2+-牛血清白蛋白的相互作用[J].西北师范大学学报(自然科学版),2010,46(4):66-69,106.
[12]周琪,林涛,谢丽,等.污水处理生物絮体絮凝沉淀机理分析的综述[J].同济大学学报(自然科学版),2009,37(1):78-83.
[13]吴守锋,斡科,郭军伟,等.重金属Hg2+离子作用于PSII23 kD外周蛋白的光谱学研究[J].天然产物研究与开发,2007,19(1):81-83,116.
[14]龙腾锐,龙向宇,唐然.胞外聚合物对生物絮凝影响的研究[J].中国给水排水,2009,25(7):30-34,40.
[2]魏焕鹏,党志,易筱筠,等.大宝山矿区水体和沉积物中重金属的污染评价[J].环境工程学报,2011,5(9):1943
[3]陈美标,郭建华,姚青,等.大宝山矿区耐Cd2+细菌的分离鉴定及其生物学特性[J].微生物学通报,2012,39(12):1720-1733.
[4]聂国朝.胞外聚合物(EPS)在藻菌生物膜去除污水中Cd的作用[J].中南民族大学学报(自然科学版),2003,22(4):16-19.
[5]李生琳.分析化学实验[M].天津:南开大学出版社,1987:73-77.
[6]张倩,李孟,王弘宇,等.反硝化除磷菌胞外聚合物的提取及除磷研究[J].武汉理工大学学报,2013,35(2):130-133.
[7]高景峰,郭建秋,陈冉妮,等.三维荧光光谱结合化学分析评价胞外多聚物的提取方法[J].环境化学,2008,27(5):662-668.
[8]邹志辉,郑凯,谭志钊,等.胞外多聚物在嗜酸氧化亚铁硫杆菌吸附Mn2+、Ni2+、Pb2+中的作用[J].环境化学,2015,34(12):2263-2267.
[9]康福星,龙健,潘响亮,等.镉对松散和紧密胞外聚合物类蛋白的荧光滴定[J].环境科学学报,2009,29(2):360-366.
[10] Bi,S. Y.,Yan,L. L.,Pang,B.,et al. Investigation of three flavonoids binding to bovine serum albumin using molecular fluorescence technique[J]. Journal of Luminescence,2012,132(1):132-140.
[11]乐薇,吴小霞.荧光法研究芦丁-Zn2+-牛血清白蛋白的相互作用[J].西北师范大学学报(自然科学版),2010,46(4):66-69,106.
[12]周琪,林涛,谢丽,等.污水处理生物絮体絮凝沉淀机理分析的综述[J].同济大学学报(自然科学版),2009,37(1):78-83.
[13]吴守锋,斡科,郭军伟,等.重金属Hg2+离子作用于PSII23 kD外周蛋白的光谱学研究[J].天然产物研究与开发,2007,19(1):81-83,116.
[14]龙腾锐,龙向宇,唐然.胞外聚合物对生物絮凝影响的研究[J].中国给水排水,2009,25(7):30-34,40.