The characteristics of nano-micron calcite particles / common bacteria complex and its interfacial interaction

Abstract

Abstract Suspended particulate in the atmosphere are composite pollutants composed of minerals, heavy metal ions, organic pollutants and microorganisms, etc. Minerals can provide shelter for living microorganisms, and forming a mineral / microorganism complex. In this paper, the nano-micron calcite particles / bacteria complex was taken as the research object, the morphology, particle size, surface electrical properties, surface groups and other characteristics of the mineral / bacteria complex were explored by modern analysis and testing methods, focusing on the analysis of the interface between mineral and bacteria in the complex. The SEM / CLSM results showed that the morphology of the complex was characterized by bacteria adhering to the surface of large particles of mineral or the aggregates of nano-mineral, and single nano-mineral particles adhering to the end and surface of bacteria. The particle size of the complex was about 2.07 ~ 192.4 times larger than that of the original mineral particles, and the particle size of nano CaCO3 / bacteria complex was larger than that of calcite / bacteria complex. The surface potential of calcite / bacteria complex is between mineral and bacteria, while the surface potential of nano CaCO3 / bacteria complex approaches mineral particles. The FTIR spectrum of mineral / bacteria complex was mainly based on the infrared characteristics of minerals, accompanied by the infrared characteristics of bacteria. Spectroscopic analysis of the secondary structure of bacterial membrane proteins in the complex showed that the calcite / bacteria complex was dominated by electrostatic attraction. The β-fold / α-helix ratio of bacteria in the mineral / Staphylococcus aureus complex increased, indicating that the secondary structure of bacteria surface proteins was more stable and the hydrogen bond effect was strong.