细菌EPS对PM_(2.5)中纳米碳酸钙表面性质的影响研究  

Effect of Two Bacterial Extracellular Polymers on the Surface Properties and Modification of Nanometer Calcium Carbonate Particles from PM_(2.5)

作　　者：赵晓夏 李琼芳[1] 董发勤[2] 代群威[3] 车明轩 董鹏举 任亚珍 ZHAO Xiaoxia;LI Qiongfang;DONG Faqin;DAI Qunwei;CHE Mingxuan;DONG Pengju;REN Yazhen(School of Life Science and Engineering,Southwest University of Science and Technology,Mianyang 621010,China;Key Laboratory of Solid Waste Treatment and Resource Recycle of Ministy of Education,Southwest University of Science and Technology,Mianyang 621010,China;National Defense Key Discipline Laboratory of Nuclear Waste and Environmental Security,Southwest University of Science and Technology,Mianyang 621010,China)

机构地区：[1]西南科技大学生命科学与工程学院,四川绵阳621010 [2]西南科技大学固体废物处理与资源化教育部重点实验室,四川绵阳621010 [3]西南科技大学核废物与环境安全国防重点学科实验室,四川绵阳621010

出　　处：《环境科学与技术》2021年第12期69-76,共8页Environmental Science & Technology

基　　金：国家自然科学基金(41130746,41472309,41877288)。

摘　　要：近年来,PM_(2.5)由于对大气环境质量和人体健康的影响而受到广泛关注。PM_(2.5)粒径小,比表面积大,活性强,易与重金属、微生物等形成复合体,增强其生物毒性。在微观环境中,微生物常会通过吸附结合并产生代谢产物来影响矿物的表面性质,为了探索微生物细胞及其胞外聚合物作用于PM_(2.5)矿物表面特性的过程和结果,该研究以常见的人体细菌:大肠杆菌和金黄色葡萄球菌作为供试菌株,以PM_(2.5)中粒径最小矿物之一的纳米碳酸钙为实验对象,研究微生物细胞及其胞外聚合物对其表面性质的影响,进而探讨对其生物毒性的改变。采用反相高效液相色谱对两株菌胞外聚合物的组成进行了表征和测定;采用电感耦合等离子体光谱、Zeta电位分析、傅里叶变换红外光谱和扫描电子显微镜,对经细菌细胞和胞外聚合物处理后的纳米碳酸钙溶液中钙离子含量,以及其残余固体表面电荷、表面基团、表面形貌进行了表征。结果表明:供试菌株胞外聚合物主要由蛋白质和多糖组成,细菌的整个细胞及其胞外聚合物作用后都能促进纳米碳酸钙颗粒溶解。由于有机基团在方解石表面的附着,纳米碳酸钙表面电位明显向负方向移动,溶液的pH明显降低,纳米碳酸钙表面形貌发生了明显变化。实验结果还进一步表明,细菌细胞及其胞外聚合物的存在显著影响了纳米碳酸钙的表面性质,将会改变超细矿物表面的微生物迁移、吸附及生物毒性,这对研究PM_(2.5)超细大气颗粒物的人体危害性及致病机理有重要意义。In recent years,PM_(2.5)has received widespread attention due to its impact on atmospheric environmental quality and human health.PM_(2.5)has a small particle size,large specific surface area,and high activity,which easily forms complexes with heavy metals and microorganisms to enhance its biotoxicity.In order to explore the process and results of the action of microbial cells and their extracellular polymers on the surface properties of PM_(2.5)minerals,this study used common human bacteria,Escherichia coli and Staphylococcus aureus,as the test strains and nano calcium carbonate,one of the smallest minerals in PM_(2.5),as the experimental target.The effect of microbial cells and their extracellular polymers on their surface properties and thus on their biotoxicity was investigated.The composition of the extracellular polymers of the two strains was characterized by reversed-phase high performance liquid chromatography,and the calcium ion content,residual solid surface charge,surface groups and surface morphology of the nano-calcium carbonate solutions treated with bacterial cells and extracellular polymers were characterized by inductively coupled plasma spectroscopy,Zeta potential analysis,Fourier transform infrared spectroscopy and scanning electron microscopy.The results showed that the extracellular polymer of the test strains consisted mainly of proteins and polysaccharides,and the whole cells of the bacteria and their extracellular polymers could promote the dissolution of calcium carbonate nanoparticles after their action.Due to the attachment of organic groups on the calcite surface,the surface potential of calcium carbonate nanoparticles shifted significantly in the negative direction,pH of the solution decreased significantly,and the surface morphology of calcium carbonate nanoparticles changed significantly.The experimental results further showed that the presence of bacterial cells and their extracellular polymers significantly affected the surface properties of calcium carbonate nanoparticles,which

关 键 词：PM_(2.5) 微生物 纳米碳酸钙 胞外聚合物 大肠杆菌 金黄色葡萄球菌 

分 类 号：X172[环境科学与工程—环境科学]