Mazanko Maria S, Mazanko Elena V, Emelyantsev Sergey A, Chikindas Michael L, Rudoy Dimitry V
Center for Agrobiotechnology, Don State Technical University, Gagarina Sq., 1, Rostov-On-Don, 344002, Russia.
Academy of Biology and Biotechnology, Southern Federal University, Stachki Ave., 194/1, Rostov-On-Don, 344090, Russia.
Braz J Microbiol. 2025 Jul 10. doi: 10.1007/s42770-025-01734-6.
Representatives of lactobacilli are among the most common probiotics, largely due to their prevalence as microorganisms involved in the fermentation of dairy products. However, research on their properties is often conducted under laboratory conditions, which are different from the conditions in the gut, making it difficult to extrapolate the obtained data. In our study, we demonstrate how the properties of two probiotic strains, Limosilactobacillus frumenti KL31 and Ligilactobacillus salivarius KL61, change under model conditions that approximate those of the gut, and we explore the relationship between lactic acid bacteria and the pH levels of the intestinal environment. Under gut-simulating conditions, lactobacilli produce less lactic acid and exhibit antioxidant and DNA-protective properties to a lesser extent than in laboratory conditions. The addition of simple or complex sugars stimulates a decrease in the pH of the model cecal contents. In turn, the pH level itself affects the growth of lactobacilli. The growth rate of Limosilactobacillus frumenti KL31 decreases when the pH of the medium increases above 7.0 since this microorganism prefers a lower pH. In contrast, Enterococcus spp. prefer a more alkaline pH, while the growth of Escherichia coli is largely independent of the environment's acidity. Due to the difficulty of assessing the probiotic properties of lactobacilli under standard laboratory conditions and the strong dependence of their growth and activity on intestinal conditions, it is necessary to use media and conditions that simulate the intestinal environment of the potential host organism when screening potential probiotic strains.
乳酸杆菌的代表菌株是最常见的益生菌之一，这主要归因于它们作为参与乳制品发酵的微生物普遍存在。然而，对其特性的研究通常是在实验室条件下进行的，这些条件与肠道中的条件不同，这使得难以推断所获得的数据。在我们的研究中，我们展示了两种益生菌菌株，即弗氏乳杆菌KL31和唾液乳杆菌KL61，在近似肠道条件的模型条件下其特性是如何变化的，并且我们探讨了乳酸菌与肠道环境pH值之间的关系。在模拟肠道条件下，乳酸杆菌产生的乳酸较少，并且与在实验室条件下相比，其抗氧化和DNA保护特性的表现程度较低。添加单糖或复合糖会促使模型盲肠内容物的pH值下降。反过来，pH值本身会影响乳酸杆菌的生长。当培养基的pH值升高到7.0以上时，弗氏乳杆菌KL31的生长速率会下降，因为这种微生物更喜欢较低的pH值。相比之下，肠球菌属更喜欢更碱性的pH值，而大肠杆菌的生长在很大程度上与环境酸度无关。由于在标准实验室条件下评估乳酸杆菌的益生菌特性存在困难，并且它们的生长和活性强烈依赖于肠道条件，因此在筛选潜在的益生菌菌株时，有必要使用模拟潜在宿主生物体肠道环境的培养基和条件。
