高效、环境友好的破乳菌在破乳过程中以胶体颗粒态存在于乳状液，其表面性质复杂，破乳机理尚未揭示。乳状液破乳的关键是液滴油水界面膜的失稳，明确菌体表面性质对其油水界面行为及界面膜稳定性的影响机制是揭示破乳机理的关键。本项目以不同类型碳源培养破乳菌，识别影响破乳性能的关键表面性质，通过原位鉴定明确影响关键表面性质的物质特征；基于自组装单分子油膜构建菌体在油水界面粘附聚集的石英晶体微天平(QCM-D)试验体系，研究不同表面性质破乳菌的界面行为特征；进一步采用自建微吸液管测试平台，研究菌体的油水界面行为对界面膜的影响规律；最后构建基于原子力显微镜(AFM)的菌体在油水界面作用力的测定体系，结合XDLVO理论研究菌体在油水界面的力学特征，并通过热力学分析揭示破乳菌表面性质对其油水界面行为的影响机制。研究成果为最终揭示破乳菌的破乳机理奠定基础，并为其他领域的菌体界面行为研究提供借鉴。

Highly-efficient and environment-friendly demulsifying bacteria has become a research hotspot in recent years. In biological demulsification process, added demulsifying cells behave like colloidal particles and exhibit complicated surface properties. However, the related demulsification mechanism remains unclear. The destabilization of oil-water interfacial film of the dispersed droplet is the key premise for the emulsion breaking process. To reveal the demulsification mechanism, it is crucial to clarify the influence of the surface properties of demulsifying bacteria on its interfacial behavior and stability of interfacial film. In this application, a selected demulsifying bacteria, Alcaligenes sp. S-XJ-1, is cultivated using different carbon sources, and the obtained cells are used as the research object. Crucial surface properties are studied followed by in-situ identification of its featured cell surface composition. The quartz crystal microbalance with dissipation (QCM-D) test system based on the single-molecule self-assembled oil monolayer is set up to characterize the interfacial behavior of demulsifying strains with different surface properties. The self-built micropipette technique testing platform is employed to study the effect of the interfacial behavior of demulsifying bacteria on the interfacial film. Finally, the interaction forces between demulsifying cells or between the interface and cells are measured using atomic force microscope (AFM). The obtained results, combined with the extended Derjaguin-Landau-Verwey-Overbeek theory (XDLVO), are cooperatively used to characterize its interfacial mechanical characteristics. Based on the thermodynamic analysis, the influence of the cell surface properties on the interfacial behavior is to be revealed. It is anticipated that this research achievements will make great contributions to the study of biological demulsification mechanism, and will provide reference for other studies focused on microbial interfacial behavior.