School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang City, 621010, Sichuan, China.
Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang City, 621010, Sichuan, China.
Environ Sci Pollut Res Int. 2023 Jun;30(28):72807-72820. doi: 10.1007/s11356-023-27522-z. Epub 2023 May 13.
Based on the composite pollution of atmospheric microbial aerosol, this paper selects the calcite/bacteria complex as the research object which was prepared by calcite particles and two common strains of bacteria (Escherichia coli, Staphylococcus aureus) in the solution system. The morphology, particle size, surface potential, and surface groups of the complex were explored by modern analysis and testing methods, with an emphasis on the interfacial interaction between calcite and bacteria. The SEM, TEM, and CLSM results showed that the morphology of the complex could be divided into three types: bacteria adhering to the surface or edge of micro-CaCO, bacteria aggregating with nano-CaCO, and single nano-CaCO wrapping bacteria. The complex's particle size was about 2.07 ~ 192.4 times larger than the original mineral particles, and the nano-CaCO/bacteria complex's particle size variation was caused by the fact that nano-CaCO has agglomeration in solution. The surface potential of the micro-CaCO/bacteria complex (isoelectric point pH = 3.0) lies between micro-CaCO and bacteria, while the surface potential of the nano-CaCO/bacteria complex (isoelectric point pH = 2.0) approaches the nano-CaCO. The complex's surface groups were based primarily on the infrared characteristics of calcite particles, accompanied by the infrared characteristics of bacteria, displaying the interfacial interaction from the protein, polysaccharides, and phosphodiester groups of bacteria. The interfacial action of the micro-CaCO/bacteria complex is mainly driven by electrostatic attraction and hydrogen bonding force, while the nano-CaCO/bacteria complex is guided by surface complexation and hydrogen bonding force. The increase in the β-fold/α-helix ratio of the calcite/S. aureus complex indicated that the secondary structure of bacterial surface proteins was more stable and the hydrogen bond effect was strong than the calcite/E. coli complex. The findings are expected to provide basic data for the mechanism research of atmospheric composite particles closer to the real environment.
基于大气微生物气溶胶的复合污染，本文选取方解石/细菌复合物作为研究对象，该复合物是通过在溶液体系中方解石颗粒和两种常见细菌（大肠杆菌、金黄色葡萄球菌）制备得到的。利用现代分析测试手段，探讨了复合物的形貌、粒径、表面电位和表面基团，重点研究了方解石与细菌之间的界面相互作用。SEM、TEM 和 CLSM 结果表明，复合物的形态可分为三种类型：细菌附着在微 CaCO 的表面或边缘、细菌与纳米 CaCO 聚集、单个纳米 CaCO 包裹细菌。复合物的粒径比原始矿物颗粒大 2.07~192.4 倍，纳米 CaCO/细菌复合物的粒径变化是由于纳米 CaCO 在溶液中团聚所致。微 CaCO/细菌复合物的表面电位（等电点 pH=3.0）介于微 CaCO 和细菌之间，而纳米 CaCO/细菌复合物的表面电位（等电点 pH=2.0）则接近纳米 CaCO。复合物的表面基团主要基于方解石颗粒的红外特征，同时伴有细菌的红外特征，从细菌的蛋白质、多糖和磷酸二酯基团方面显示了界面相互作用。微 CaCO/细菌复合物的界面作用主要由静电引力和氢键力驱动，而纳米 CaCO/细菌复合物则由表面络合和氢键力引导。方解石/金黄色葡萄球菌复合物中β折叠/α螺旋比例的增加表明，细菌表面蛋白的二级结构比方解石/大肠杆菌复合物更稳定，氢键作用更强。研究结果有望为更接近实际环境的大气复合颗粒的机制研究提供基础数据。
