三株细菌胞外聚合物（EPS）对矿物细颗粒表面性质的影响及改性作用

发布时间：2018-08-03 19:24

【摘要】：随着经济的快速发展、城镇化进程加快,大气可吸入颗粒物污染日趋严重,严重影响着人类的身体健康。矿物细颗粒和微生物同时作为大气污染物的主要组成成分,目前,微生物活体细胞对矿物细颗粒的毒性研究、表面性质的相关研究还很有限。胞外聚合物(extracellular polymeric substances,EPS)在微生物对矿物作用过程中起着重要作用。因此,细菌EPS对大气矿物细颗粒作用的相关研究显得非常必要。本文以大气颗粒物中典型的矿物方解石、纳米碳酸钙、石英、纳米二氧化硅和钠长石为研究对象。选取土壤常驻菌(即硅酸盐细菌)、空气常见致病菌(即金黄色葡萄球菌)和人体正常菌(即大肠杆菌)为实验菌株,目的是分析矿物细颗粒从土壤—空气—人体过程中与不同常见菌之间的作用过程。通过高效液相色谱法定性、定量分析了三株常见细菌EPS主要成分(即胞外低分子有机酸、氨基酸及多糖中的单糖成分)。利用等离子发射光谱仪(ICP)、X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)、傅里叶红外光谱仪(FTIR)、扫描电镜(SEM)、Zeta电位分析仪等分析测试手段,考察了三株细菌及其EPS和EPS主要成分对矿物细颗粒溶出离子、表面电性、表面基团和表面形貌的影响。结果如下:(1)三株常见细菌EPS主要成分特征表现:有机酸主要组分包括草酸、乳酸、琥珀酸和柠檬酸;氨基酸主要组分包括组氨酸、精氨酸、酪氨酸和胱氨酸;多糖水解液中的单糖主要组分包括甘露糖、核糖和葡萄糖醛酸。(2)三株细菌EPS均能使五种矿物表面性质(溶出离子、表面电性、表面基团和表面形貌)发生明显变化,其中对碳酸盐矿物的影响大于硅铝酸盐矿物大于硅酸盐矿物,即几种矿物表面性质的变化程度为方解石钠长石石英,纳米碳酸钙纳米二氧化硅。(3)三株细菌EPS对微米级矿物和纳米级矿物影响差异较大,纳米级矿物表面具有高的化学活性和吸附能力,使其更容易与有机物发生反应。溶出离子结果表明,有机酸、氨基酸和单糖对纳米级矿物的溶出离子明显高于微米级矿物,FTIR结果表明,纳米级矿物表面能吸附更多的有机物或有机物基团,其吸附能力明显高于微米级矿物,而纳米颗粒的表面能高使有机酸、氨基酸和单糖对其表面电性的影响明显小于微米级矿物。细菌EPS对矿物颗粒表面性质的影响明显大于EPS主要成分,当细菌或者细菌EPS对纳米级矿物作用时,纳米颗粒表面的这种特性被打破,由Zeta电位结果可知,细菌及其细菌EPS能明显使纳米级矿物表面Zeta电位向负电荷方向发生明显移动。(4)细菌EPS对矿物细颗粒表面性质的影响过程中,对矿物表面性质的影响顺序为细菌大于细菌的EPS大于去EPS后菌体。SEM图结果表明,在细菌对矿物表面形貌的影响过程中,EPS起主要贡献作用。综上所述,三株细菌EPS对实验所选五种矿物表面性质均有显著影响,不同细菌EPS对同一矿物影响不同,同一细菌EPS对不同矿物表面性质影响不同,同一细菌EPS对微米级矿物和纳米级矿物影响有明显差异,这与细菌EPS的组分和矿物表面的性质密切相关。以上结果表明,矿物细颗粒在整个迁移过程中表面性质发生着不断的变化,特别是有毒有害的Si离子的溶出,从而达到了对矿物细颗粒改性的效果,使其最终到达人体时,对人体的危害减弱,对可吸入矿物细颗粒的健康影响等综合评价体系研究具有重要的科学意义。
[Abstract]:With the rapid development of economy and the accelerated process of urbanization, the pollution of inhalable particulate matter in the atmosphere is becoming more and more serious, which seriously affects human health. Mineral fine particles and microbes are the main components of the air pollutants at the same time. At present, the study on the toxicity of microbiological cells to mineral fine particles and the related research on the surface properties It is very limited. Extracellular polymers (extracellular polymeric substances, EPS) play an important role in the action of microbes on mineral action. Therefore, it is necessary to study the effect of bacterial EPS on the fine particles of atmospheric minerals. This paper is based on the typical mineral quartzite, nano calcium carbonate, quartz, nano silica and sodium in atmospheric particles. The objective of this study is to select the soil permanent bacteria (silicate bacteria), the common pathogenic bacteria in the air (Staphylococcus aureus) and human normal bacteria (E. coli) as experimental strains. The purpose is to analyze the process of the action of mineral fine particles from the soil to the human body in the course of the soil air human process. Sex, quantitative analysis of the main components of three common bacteria EPS (namely, extracellular low molecular organic acids, amino acids and monosaccharides in polysaccharides). Using plasma emission spectrometer (ICP), X ray fluorescence spectrometer (XRF), X ray diffractometer (XRD), Fourier infrared spectrometer (FTIR), scanning electron microscope (SEM), Zeta potential analyzer and other analytical testing means The effects of three strains of bacteria and their main components of EPS and EPS on the dissolution of mineral particles, surface electricity, surface groups and surface morphology were investigated. The results were as follows: (1) the main components of three common bacteria EPS: the main components of organic acids include oxalic acid, lactic acid, succinic acid and citric acid; the main components of amino acids include histidine, arginine, The main components of monosaccharide in the polysaccharide aqueous solution include mannose, ribose and glucuronic acid. (2) three bacterial EPS can make the surface properties of five minerals (dissolved ions, surface electricity, surface groups and surface morphology) obviously change, and the effect on carbonate minerals is greater than that of silicates than silicate minerals. The surface properties of mineral, that is, the surface properties of several minerals are calcite sodium feldspar quartz, nano calcium carbonate nanoscale silica. (3) three strains of bacteria EPS have great influence on micron and nanoscale minerals. The surface of nanoscale minerals has high chemical activity and adsorption capacity, which makes it easier to react with organic matter. The results show that the dissolved ions of organic acids, amino acids and monosaccharides are significantly higher than those of micron grade minerals. The results of FTIR show that the surface of nanoscale minerals can adsorb more organic or organic groups, and their adsorption capacity is higher than that of micron grade minerals, while the surface of nanoscale particles can make organic acids, amino acids and monosaccharides on their surface. The effect of surface electricity is obviously smaller than that of micron grade minerals. The effect of bacterial EPS on the surface properties of mineral particles is obviously greater than that of EPS. When bacteria or bacterial EPS acts on nanoscale minerals, the properties of the nanoparticles are broken. From the Zeta potential results, the bacteria and their bacterial EPS can obviously make the nanoscale mineral surface Zeta (4) the effect of EPS on the surface properties of mineral particles in the process of the effect of bacteria on the surface properties of mineral particles, the order of the effect of the surface properties of the mineral on the surface properties of the bacteria is that the EPS of bacteria is greater than that of the EPS, and the result of the.SEM map of the bacteria shows that in the process of the effect of the bacteria on the surface morphology of the minerals, EPS plays the main role. In summary, three Bacterial EPS has significant influence on the surface properties of the five minerals selected by the experiment. The influence of different bacteria EPS on the same mineral is different. The effect of the same bacteria EPS on the surface properties of different minerals is different. The influence of the same bacteria EPS on the micron and nanoscale minerals is obviously different, which is closely related to the composition of the bacterial EPS and the properties of the mineral surface. The above results show that the surface properties of mineral fine particles are constantly changed during the whole process of migration, especially the dissolution of toxic and harmful Si ions, thus reaching the effect on the modification of mineral fine particles, and the harm to the human body is weakened and the health effect on the fine particles of the minerals can be evaluated. The study of price system is of great scientific significance.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X513;X172;O631.3

【参考文献】