The cell membrane of lactic acid bacteria (LAB) functions as a crucial barrier against external conditions. Spray drying, a technique used for large-scale bacterial powder production, exposes cells to high temperatures, resulting in membrane damage. In this study, three strains of Bifidobacterium animalis A12, F1–7, and KV9 with significant differences in survival rates after spray drying (47.28 ± 9.00, 11.12 ± 2.62, and 37.44 ± 0.22%, respectively) were selected for analysis. A12 exhibited the strongest SYTO-9 fluorescence intensity, indicating the highest membrane integrity after spray drying. Subsequently, UHPLC-Q-Exactive MS-based lipidomics identified two key lipid species, fatty acyl 18:1; O3 and cardiolipin 15:0_18:0_28:0_22:5, which were potentially crucial for bacterial membrane heat resistance. KEGG pathway analysis further revealed that glycerophospholipid metabolism was the most significantly enriched pathway. This study provides insights into critical membrane lipids that contribute to the heat resistance of B. animalis during spray drying, offering a theoretical reference for screening stress-resistant LAB.

中文翻译：

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非靶向脂质组学揭示了具有不同喷雾干燥性的三种动物双歧杆菌菌株中的关键膜脂质

乳酸菌 （LAB） 的细胞膜是抵御外部条件的重要屏障。喷雾干燥是一种用于大规模细菌粉末生产的技术，可将细胞暴露在高温下，导致细胞膜损伤。本研究选择喷雾干燥后存活率差异显著的 3 株动物双歧杆菌 A12 、 F1-7 和 KV9 菌株 （分别为 47.28 ± 9.00、11.12 ± 2.62 和 37.44 ± 0.22% ）进行分析。A12 表现出最强的 SYTO-9 荧光强度，表明喷雾干燥后膜完整性最高。随后，基于 UHPLC-Q-Exactive MS 的脂质组学鉴定了两种关键脂质种类，即脂肪酰基 18：1;O3 和心磷脂 15：0_18：0_28：0_22：5，它们对细菌膜耐热性可能至关重要。KEGG 通路分析进一步显示，甘油磷脂代谢是最显著富集的通路。本研究对影响动物双歧杆菌喷雾干燥过程中耐热性的关键膜脂提供了见解，为筛选抗逆性 LAB 提供了理论参考。