Apostolakos Ilias, Paramithiotis Spiros, Mataragas Marios
Department of Dairy Research, Institution of Technology of Agricultural Products, Hellenic Agricultural Organization "DIMITRA", 3 Ethnikis Antistaseos St., 45221 Ioannina, Greece.
Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos St., 11855 Athens, Greece.
Foods. 2023 Feb 1;12(3):599. doi: 10.3390/foods12030599.
Lactic acid bacteria (LAB) are valuable for the production of fermented dairy products. We investigated the functional traits of LAB isolated from artisanal cheeses and raw sheep milk, assessed their safety status, and explored the genetic processes underlying the fermentation of carbohydrates. had the largest and more functional genome compared to all other LAB, while most of its protein-encoding genes had unknown functions. A key finding of our analysis was the overall absence of acquired resistance genes (RGs), virulence genes (VGs), and prophages, denoting that all LAB isolates fulfill safety criteria and can be used as starter or adjunct cultures. In this regard, the identified mobile genetic elements found in LAB, rather than enabling the integration of RGs or VGs, they likely facilitate the uptake of genes involved in beneficial functions and in the adaptation of LAB in dairy matrices. Another important finding of our study was that bacteriocins and CAZymes were abundant in LAB though each species was associated with specific genes, which in turn had different activity spectrums and identified applications. Additionally, all isolates were able to metabolize glucose, lactose, maltose, and sucrose, but was strongly associated with the fermentation of rhamnose, mannose, cellobiose, and trehalose whereas with the utilization of arabinose and xylose. Altogether these results suggest that to fully exploit the beneficial properties of LAB, a combination of strains as food additives may be necessary. Interestingly, biological processes involved in the metabolism of carbohydrates that are not of direct interest for the dairy industry may yield valuable metabolites or activate pathways associated with beneficial health effects. Our results provide useful information for the development of new probiotic artisanal cheeses and probiotic starter cultures.
乳酸菌（LAB）对于发酵乳制品的生产具有重要价值。我们研究了从手工奶酪和生羊奶中分离出的乳酸菌的功能特性，评估了它们的安全状况，并探索了碳水化合物发酵的潜在遗传过程。与所有其他乳酸菌相比，[具体菌株名称未给出]具有最大且功能更多的基因组，但其大多数蛋白质编码基因的功能未知。我们分析的一个关键发现是总体上不存在获得性抗性基因（RGs）、毒力基因（VGs）和前噬菌体，这表明所有乳酸菌分离株均符合安全标准，可作为发酵剂或辅助培养物使用。在这方面，在乳酸菌中发现的已鉴定移动遗传元件，并非促进RGs或VGs的整合，而是可能促进参与有益功能的基因的摄取以及乳酸菌在乳制品基质中的适应性。我们研究的另一个重要发现是，乳酸菌中细菌素和碳水化合物活性酶（CAZymes）丰富，尽管每个物种都与特定基因相关，而这些基因又具有不同的活性谱和已确定的应用。此外，所有分离株都能够代谢葡萄糖、乳糖、麦芽糖和蔗糖，但[具体菌株名称未给出]与鼠李糖、甘露糖、纤维二糖和海藻糖的发酵密切相关，而[具体菌株名称未给出]与阿拉伯糖和木糖的利用有关。总之，这些结果表明，为了充分利用乳酸菌的有益特性，可能需要将多种菌株组合作为食品添加剂。有趣的是，碳水化合物代谢中涉及的对乳制品行业无直接兴趣的生物学过程可能产生有价值的代谢物或激活与有益健康影响相关的途径。我们的结果为新型益生菌手工奶酪和益生菌发酵剂培养物的开发提供了有用信息。
