本文利用代谢组学方法，对比研究了添加不同冻干保护剂对植物乳杆菌dy-1（L.P dy-1）冻干菌粉发酵过程中代谢途径的影响。研究采用气质联用技术（GC-MS）分析菌体胞内代谢物，通过偏最小二乘法（PLS）和模式识别分析不同冻干保护剂组的差异代谢物，并结合KEGG等数据库对差异变量参与的代谢途径进行解析。结果表明，分别添加10%菊粉、22.4%菊粉、菊粉复合保护剂和脱脂乳复合保护剂，对L.P dy-1冻干粉发酵过程中的能量代谢、氨基酸代谢和脂肪酸代谢的影响存在差异：菊粉的添加量由10%增加至22.4%，冻干菌粉与直接活化菌体在发酵过程中的代谢特征差异缩小；与脱脂乳复合保护剂相比，菊粉复合保护剂能够使冻干菌体在代谢特征上更接近于直接活化菌体。贮藏温度对冻干菌粉的代谢影响显著：与4 ℃相比，-20 ℃贮藏冻干菌粉更有利于维持菌体在发酵过程中的正常代谢。

The effects of different cryoprotectants on the metabolic pathways of freeze-dried Lactobacillus plantarum dy-1 (L. P dy-1) powder during fermentation were analyzed through a metabolomics study. The intracellular metabolites of L. P dy-1 were separated and analyzed by gas chromatography-mass spectrometry. The metabolites produced in the presence of the different cryoprotectantss were identified and analyzed by using pattern recognition and partial least squares methods, and were employed to reconstruct the metabolic pathways using the Kyoto Encyclopedia of Genes and Genomes database. The results indicated that 10% inulin, 22.4% inulin, inulin composite protective agent, or skim milk composite protective agent showed different impacts on the energy metabolism, amino acid metabolism, and fatty acid metabolism in the fermentation of freeze-dried L. P dy-1. When the inulin content was increased from 10% to 22.4%, the differences in metabolic characteristics between freeze-dried bacteria and directly activated bacterial cells decreased. The metabolic characteristics of freeze-dried L. P dy-1 were closer to those of directly activated bacterial cells when using the inulin composite protective agent than when using the skim milk composite protective agent. Storage temperature had a significant effect on the metabolism of the freeze-dried bacteria; storage at -20 ℃ was more beneficial than storage at 4 ℃ to maintain the normal metabolism of L. P dy-1 during fermentation.

江苏高校优势学科建设工程项目；江苏大学高级人才专项（1281360027）