奶粉加工过程中的嗜热菌及其生物膜形成机制研究

Biofilm formation of thermophilic aerobic sporeforming bacteria in the milk powder process is a worldwide problem, which is the potential risk and can cause the damage to the quality of dairy products. Based on our previous studies, this proposal aims to reveal the microflora of thermophilic aerobic sporeforming bacteria both in the milk products and biofilm collected from milk powder process. Mechanism of biofilm formation will be explored by transcriptomics. Proteomics will be used to understand the regulation of key proteins in the process of biofilm formation, to clarify the function of protein and screen out key proteins that influence the formation of biofilm. The key difference of metabolic pathways of planktonic culture and biofilm will also be explored by metabolomics. Meanwhile, signals of quorum sensing and the effect on the biofilm formation will also be determined, establishing a link between quorum sensing and biofilm formation. For the purpose of regulating the biofilm formation, getting food grade quorum sensing inhibitors is also of great importance. Mechanisms of biofilm formation in thermophilic aerobic sporeforming bacteria will be clarified in this proposal, providing theoretical and scientific basis for the prevention of biofilm in dairy industries.

奶粉加工过程中由嗜热菌形成生物膜结构的现象是全世界乳制品行业棘手的技术难题，不仅对乳制品品质造成危害，也带来乳制品食用安全的潜在风险。本项目在原有研究基础上，首先解析奶粉产品及奶粉加工设备中生物膜的嗜热菌菌群结构;采用转录组学方法探索嗜热菌的生物膜形成机制；并结合蛋白组学阐明生物被膜形成过程中关键蛋白的调控情况，明确蛋白功能，筛选出能影响生物被膜形成的关键蛋白；采用代谢组学比较浮游态和生物膜状态下的嗜热菌代谢途径，找出成膜的群体感应分子；同时监控生物膜形成过程中微生物生长和群体感应信号分子，探索群体感应对生物膜形成的影响；寻找合适的群体感应信号分子抑制剂，基于分子手段与群感效应淬灭理论来调控生物膜的形成。本项目研究结果将明确奶粉加工过程中嗜热菌的生物膜形成机制，为防控乳制品加工过程中嗜热菌生物膜的形成和保障我国乳制品产品质量与安全提供理论基础和科学依据。

在奶粉的加工过程中，嗜热菌的存在是一个令全球乳品工厂棘手的问题。本项目探究了奶粉产品中嗜热菌的分离培养与基于RAPD的菌群结构，跟踪测定了奶粉生产过程中样品中的嗜热菌种类与数目，明确了优势嗜热菌种类与关键增殖位点；测定了多株优势的生物膜的形成能力，并研究了优势菌株分别在单菌培养与混合培养时的生物膜形成能力差异；综合利用转录组学、蛋白质组学以及代谢组学揭示了优势嗜热菌地衣芽孢杆菌生物膜的形成机制；利用群体感应信号分子报告细菌的生物感应等方法测定了不同嗜热菌生物膜群体感应信号分子的种类和活性强度，发现了植物乳杆菌天然代谢物能够抑制地衣芽孢杆菌生物膜的形成。本项目为明确奶粉加工过程主要微生物污染源的生理特性与作用机制、开发有效的生物膜抑制方法提供了理论基础，有助于提升奶粉产品质量、构建乳制品加工的微生物安全防控体系。