UMR GMPA, AgroParisTech, INRA, Université Paris-Saclay, 78850, Thiverval-Grignon, France.
Laboratorio de Microbiología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Bernal, Argentina.
Appl Microbiol Biotechnol. 2019 Sep;103(17):6867-6883. doi: 10.1007/s00253-019-10002-1. Epub 2019 Jul 12.
Production of lactic acid bacteria starters for manufacturing food, probiotic, and chemical products requires the application of successive steps: fermentation, concentration, stabilization, and storage. Despite process optimization, losses of bacterial viability and functional activities are observed after stabilization and storage steps due to cell exposure to environmental stresses (thermal, osmotic, mechanical, and oxidative). Bacterial membrane is the primary target for injury and its damage is highly dependent on its physical properties and lipid organization. Membrane fluidity is a key property for maintaining cell functionality, and depends on lipid composition and cell environment. Extensive evidence has been reported on changes in membrane fatty acyl chains when modifying fermentation conditions. However, a deep characterization of membrane physical properties and their evolution following production processes is scarcely reported. Therefore, the aims of this mini-review are (i) to define the membrane fluidity and the methods used to assess it and (ii) to summarize the effect of environmental conditions on membrane fluidity and the resulting impact on the resistance of lactic acid bacteria to the stabilization processes. This will make it possible to highlight existing gaps of knowledge and opens up novel approaches for future investigations.
生产用于制造食品、益生菌和化学产品的乳酸菌发酵剂需要应用连续的步骤：发酵、浓缩、稳定和储存。尽管进行了工艺优化，但由于细胞暴露于环境应激（热、渗透、机械和氧化），在稳定和储存步骤后仍会观察到细菌活力和功能活性的损失。细菌膜是损伤的主要靶标，其损伤高度依赖于其物理性质和脂质组织。膜流动性是维持细胞功能的关键特性，取决于脂质组成和细胞环境。已经有大量关于改变发酵条件时膜脂肪酸链变化的报道。然而，对于生产过程中膜物理性质及其演变的深入表征却鲜有报道。因此，本篇迷你综述的目的是：(i) 定义膜流动性和用于评估膜流动性的方法；(ii) 总结环境条件对膜流动性的影响，以及对乳酸菌对稳定过程的抗性的影响。这将有助于突出现有知识差距，并为未来的研究开辟新的途径。
