Bifidobacterium longum NCIM 5672 is a probiotic strain isolated from the Indian infant feces. The probiotic efficacy of Bifidobacteria is majorly affected by its acid tolerance. This study determined the probiotic properties and acid-tolerance mechanism of B. longum NCIM 5672 using whole-genome sequencing. The genome annotation is carried out using the RAST web server and NCBI PGAAP. The draft genome sequence of this strain, assembled in 63 contigs, consists of 22,46,978 base pairs, 1900 coding sequences and a GC content of 59.6%. The genome annotation revealed that seven candidate genes might be involved in regulating the acid tolerance of B. longum NCIM 5672. Furthermore, the presence of genes associated with immunomodulation and cell adhesion support the probiotic background of the strain. The analysis of candidate acid- tolerance-associated genes revealed three genes, argC, argH, and dapA, may play an essential role in high acid tolerance in B. longum NCIM 5672. The results of RT-qPCR supported this conclusion. Altogether, the results presented here supply an effective way to select acid-resistant strains for the food industry and provide new strategies to enhance this species' industrial applications and health-promoting properties.

长双歧杆菌NCIM 5672 是一种从印度婴儿粪便中分离出来的益生菌菌株。双歧杆菌的益生菌功效主要受其耐酸性影响。本研究使用全基因组测序确定了长双歧杆菌NCIM 5672的益生菌特性和耐酸机制。基因组注释是使用 RAST 网络服务器和 NCBI PGAAP 进行的。该菌株的基因组序列草图由 63 个重叠群组装而成，由 22,46,978 个碱基对、1900 个编码序列和 59.6% 的 GC 含量组成。基因组注释显示7个候选基因可能参与调节长双歧杆菌的耐酸能力NCIM 5672。此外，与免疫调节和细胞粘附相关的基因的存在支持该菌株的益生菌背景。候选酸耐受相关基因的分析揭示了三个基因，arg C、arg H 和dap A，可能在B. longum NCIM 5672 的高酸耐受性中起重要作用。 RT-qPCR 的结果支持这一结论。总而言之，这里介绍的结果提供了一种为食品工业选择耐酸菌株的有效方法，并提供了新的策略来增强该物种的工业应用和促进健康的特性。