环二肽Cyclo（Leu-Pro）对植物乳杆菌的促生长作用

Growth-promoting Effect of Cyclic Dipeptide Cyclo (Leu-Pro) on Lactobacillus plantarum

摘要:

研究旨在探讨环二肽Cyclo（Leu-Pro）对植物乳杆菌生长的影响。该研究以植物乳杆菌（Lactobacillus plantarum T1）为研究对象，采用高效液相色谱法初步定性定量植物乳杆菌T1发酵液中的Cyclo（Leu-Pro），然后将植物乳杆菌T1分别接种于不含或含不同质量浓度（0.5、1、5、10 μg/mL）Cyclo（Leu-Pro）的MRS肉汤培养基中培养18 h，采用96孔法和平板计数法测定不同培养条件下植物乳杆菌T1的生长曲线和活菌数。结果表明：不同质量浓度的Cyclo（Leu-Pro）对植物乳杆菌T1的生长均有明显的促生长作用，其中，1 μg/mL Cyclo（Leu-Pro）的促生长效果最佳，可将活菌数提高到8.73×1010 CFU/mL，相比于对照组提高了一个数量级。在不同胁迫条件下，1 μg/mL Cyclo（Leu-Pro）能使植物乳杆菌T1的延滞期缩短、生长速度提高，其活菌数和生物量显著增加（P<0.05）。综上所述，Cyclo（Leu-Pro）促进了植物乳杆菌T1的生长，增强了其抗胁迫能力。这将有利于植物乳杆菌T1作为发酵剂在食品发酵领域的应用。

Abstract:

In this study, it’s the effect of Cycle (Leu-Pro) on the growth of Lactobacillus plantarum was investigated. Lactobacillus Plantarum T1 was used as the research object, and high-performance liquid chromatography (HPLC) was used to preliminarily characterize and quantify the Cyclo (Leu-Pro) in the fermentation broth of Lactobacillus Plantarum T1. Lactobacillus Plantarum T1 was respectively inoculated in the MRS broth medium without or with different mass concentrations (0.5, 1, 5, 10 μg/mL) of Cyclo (Leu-Pro) for 18 h. The growth curves and viable bacterial counts of Lactobacillus plantarum T1 under different culture conditions were determined by the 96-well method and plate counting method. The results showed that Cyclo (Leu-Pro) at different mass concentrations had significant growth-promoting effects on the growth of Lactobacillus plantarum T1, among which, 1 μg /mL Cyclo (Leu-Pro) had the greatest growth-promoting effect and could increase the viable counts to 8.73×1010 CFU/mL, which was an order of magnitude higher than the control. Under different stress conditions, 1 μg/mL Cyclo (Leu-Pro) could shorten the lag period and increase the growth rate of Lactobacillus plantarum T1, and its viable count and biomass increased significantly (P<0.05). In summary, Cyclo (Leu-Pro) promoted the growth of Lactobacillus plantarum T1 and enhanced its stress resistance. This will favor the application of Lactobacillus plantarum T1 as a starter in the field of food fermentation.