腌腊鱼中特定乳酸菌AI-2/LuxS群体感应及其对制品风味形成调控机制

Cured fish is a traditional aquatic processed product in China. Flavor and safety are important indexes to evaluate its quality. Lactic acid bacteria are dominant bacteria and play an important role in flavor formation in cured fish. Studies showed that AI-2/LuxS based quorum sensing could regulate food quality by influence the metabolites of specific lactic acid bacteria, but the regulation mechanism is not clear. In this proposal, AI-2/LuxS based quorum sensing of cured fish during fermentation is analyzed using molecular biology methods. The changes of microbial community during the fermentation are investigated by traditional isolation method and metagenomics technique. The specific lactic acid bacteria and its AI-2/LuxS based quorum sensing system are identified. The correlation of quorum sensing, microbial community and flavor quality of cured fish is discussed. The potential targeted genes for flavor formation are identified by transcriptomics and proteomics analysis. The gene mutants are constructed and metabolomics analysis is conducted to clarify the regulation mechanism of LuxS-dependent quorum sensing of lactic acid bacteria on flavor formation in cured fish. The results of the present study will provide necessary scientific theoretical basis for promoting the flavor quality of fermented aquatic products through regulating the AI-2/LuxS-dependent quorum sensing of specific lactic acid bacteria.

腌腊鱼是我国传统特色水产加工制品，风味和食用安全性是评价其品质的重要指标。乳酸菌作为其中的优势菌群对腌腊鱼制品风味等品质的形成具有重要作用。初步研究表明，AI-2信号分子介导的LuxS群体感应系统能通过调控乳酸菌代谢而影响腌腊鱼产品品质的形成，但目前其具体调控机制尚未明确。鉴于此，本项目拟以传统腌腊鱼为研究对象，通过选择性分离培养及宏基因组测序技术对腌腊鱼发酵过程中的菌相变化进行分析，在此基础上，分离鉴别其中的特定优势乳酸菌，分析典型乳酸菌的AI-2/LuxS群体感应，探讨群体感应与腌腊鱼微生物组成、风味等品质的相关性；同时基于转录组与蛋白质组学分析鉴别乳酸菌LuxS靶向调控风味物质形成关键基因，并在构建基因缺失株的基础上，通过代谢组学方法解析LuxS群体感应介导腊鱼风味品质形成的分子机理。研究结果将为以特定乳酸菌的AI-2/LuxS群体感应为切入点提升传统发酵水产品风味特征提供理论依据。

腌腊鱼是我国传统特色水产加工制品，风味和使用安全性是评价其品质的重要指标。微生物代谢在发酵鱼制品风味形成起着至关重要的作用。本项目以草鱼为研究对象，分析了草鱼在传统发酵工艺、乳酸菌发酵工艺中微生物组成、风味特性的变化，解析了基于微生物代谢调控的发酵鱼制品风味形成机制。研究结果表明，海科贝特氏菌、葡萄球菌属和罗尔斯顿属是腌腊鱼优势属。腌腊鱼发酵过程中醛类、醇类、小肽类、游离氨基酸和羧酸的丰度显著增加，影响了腌腊鱼的风味品质。特定微生物与特征性挥发性物质、风味代谢物显著相关（P < 0.05）。葡萄球菌作为优势菌属，参与腌腊鱼发酵过程中风味形成机制。植物乳杆菌发酵草鱼后微生物组成和蛋白质谱发生显著变化。巨球菌和葡萄球菌是发酵草鱼的优势属。发酵草鱼的风味相关蛋白与这些菌及主要肽酶基因显著相关（P < 0.05）。本项目的实施对利用微生物发酵剂提升发酵鱼制品风味具有重要意义。