Functional foods and nutraceuticals frequently contain viable probiotic strains that, at certain titers, are considered to be responsible of beneficial effects on health. Recently, it was observed that secreted metabolites might play a key role in this respect, especially in immunomodulation. Exopolysaccharides produced by probiotics, for example, are used in the food, pharmaceutical, and biomedical fields, due to their unique properties. Lactobacillus brevis CD2 demonstrated the ability to inhibit oral pathogens causing mucositis and periodontal inflammation and to reduce Helycobacter pylori infections. Due to the lack of literature, for this strain, on the development of fermentation processes that can increase the titer of viable cells and associated metabolites to industrially attractive levels, different batch and fed-batch strategies were investigated in the present study. In particular, aeration was shown to improve the growth rate and the yields of lactic acid and biomass in batch cultures. The use of an exponential feeding profile in fed-batch experiments allowed to produce 9.3 ± 0.45 × 10⁹ CFU/mL in 42 h of growth, corresponding to a 20-fold increase of viable cells compared with that obtained in aerated batch processes; moreover, also increased titers of exopolysaccharides and lactic acid (260 and 150%, respectively) were observed. A purification process based on ultrafiltration, charcoal treatment, and solvent precipitation was applied to partially purify secreted metabolites and separate them into two molecular weight fractions (above and below 10 kDa). Both fractions inhibited growth of the known gut pathogen, Salmonella typhimurium, demonstrating that lactic acid plays a major role in pathogen growth inhibition, which is however further enhanced by the presence of Lact. brevis CD2 exopolysaccharides. Finally, the EPS produced from Lact. brevis CD2 was characterized by NMR for the first time up to date.

功能性食品和营养保健品经常含有可行的益生菌菌株，这些菌株在某些滴度下被认为对健康有益。最近，观察到分泌的代谢产物可能在这方面起关键作用，特别是在免疫调节中。由益生菌产生的胞外多糖，由于其独特的性质，例如，被用于食品，制药和生物医学领域。短乳杆菌CD2具有抑制引起粘膜炎和牙周炎的口腔病原体和减少幽门螺杆菌的能力感染。由于缺乏文献，对于这种菌株，在发酵过程的发展上可以将活细胞和相关代谢产物的效价提高到工业上有吸引力的水平，因此在本研究中研究了不同的分批和补料分批策略。特别地，显示出通气改善了分批培养物中的生长速率以及乳酸和生物质的产量。在补料分批实验中使用指数补料曲线可以产生9.3±0.45×10 ⁹ 生长42小时的CFU / mL，与充气分批工艺相比，相当于活细胞增加了20倍；此外，还观察到胞外多糖和乳酸的滴度增加（分别为260％和150％）。应用基于超滤，木炭处理和溶剂沉淀的纯化工艺来部分纯化分泌的代谢物，并将其分为两个分子量级分（高于和低于10 kDa）。这两个部分均抑制已知肠道病原体鼠伤寒沙门氏菌的生长，表明乳酸在病原体生长抑制中起主要作用，然而，乳酸的存在会进一步增强乳酸。brevis CD2外多糖。最后，由Lact生产的EPS 。布雷维斯 迄今为止，首次通过NMR对CD2进行了表征。