Investigating the Role of Membrane Lipid Composition Differences on Spray Drying Survival in Lactobacillus Bulgaricus Using Non-Targeted Lipidomics

Abstract

The cell membrane, consisting of the phospholipid bilayer, is an important defense of the lactic acid bacteria (LAB) against external stress conditions. However, it was usually damaged during the process of LAB being spray dried into powder. In this study, Lactobacillus bulgaricus L9-7 and L4-2-12 with significantly different survival rates after spray drying (about 22.49% and 0.43%) were chosen. A total of 65 differential lipid species were screened between two strains and highly resistant L9-7 contained 0.31% of cardiolipin, significantly higher than that of L4-2-12. CL 15:1_22:6_24:0_28:0 might be the characteristic lipid species affecting membrane resistance. KEGG enrichment analysis revealed glycerophospholipid metabolism was the most predominant pathway and seven lipid species were annotated. This paper aims to explore the critical lipid species that may affect the ability of Lactobacillus bulgaricus to resist spray drying from the cell membrane level, and provides valuable insights into enhancing the heat tolerance of LAB.

Keywords: Lactobacillus bulgaricus, Membrane lipid composition, Non-targeted Lipidomics, spray drying, Survival rate