Water kefir is a fermented beverage employing a natural microbial consortium, which harbours bifidobacteria, namely Bifidobacterium aquikefiri and Bifidobacterium tibiigranuli. However, little information is available on their metabolic properties or role in the consortium. In this study, we combined genomic and physiologic investigations to predict and characterize the properties of these organisms and their possible role in the consortium. When comparing the genomes of these psychrotrophic organisms with that of the three selected mesophilic probiotic Bifidobacterium strains, we could find 143 genes shared by the 3 known isolates of bifidobacteria from water kefir that do not occur in the probiotic strains. These include genes involved in acid and oxygen tolerance. In addition, their genomically predicted carbohydrate usage and transport suggest adaptation to sucrose and other plant-related sugars. Furthermore, they proved prototrophic for all amino acids in vitro, which enables them to cope with the strong amino acid limitation in water kefir.

中文翻译：

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水开菲尔双歧杆菌生活方式的基因组学和生理学见解

水开菲尔是一种采用天然微生物群落的发酵饮料，其中含有双歧杆菌，即双歧杆菌 aquikefiri 和 Bifidobacterium tibiigranuli。然而，关于它们的代谢特性或在联盟中的作用的信息很少。在这项研究中，我们结合基因组和生理学研究来预测和表征这些生物的特性及其在财团中的可能作用。当将这些嗜冷生物的基因组与三个选定的嗜温益生菌双歧杆菌菌株的基因组进行比较时，我们可以找到 143 个基因，这些基因由来自水开菲尔的 3 种已知双歧杆菌分离物共享，而这些基因在益生菌菌株中不存在。这些包括与耐酸和耐氧有关的基因。此外，他们的基因组预测碳水化合物的使用和运输表明对蔗糖和其他植物相关糖的适应。此外，它们在体外证明对所有氨基酸都是原养的，这使它们能够应对水开菲尔中的强氨基酸限制。