Complete-genome sequence and in vitro probiotic characteristics analysis of Bifidobacterium pseudolongum YY-26

Aims: The aim was to isolate a neotype bifidobacteria strain and evaluate its in vitro probiotic potential.

Methods and results: Bifidobacterium pseudolongum YY-26 (CGMCC 24310) was isolated from faeces of mice treated with low-molecular-weight hydrolyzed guar gum (GMPS) and identified based on 16S rRNA sequence and genome sequence. Whole-genome sequencing obtained using PacBio's single-molecular and Illumina's paired-end sequencing technology. A genome of 2.1 Mb in length, with 1877 predicted protein-coding sequences was obtained. Carbohydrate-Activity enZyme analysis revealed that YY-26 encodes 66 enzymes related to carbohydrate metabolism. Whole genome sequence analysis revealed the typical probiotic characteristics of YY-26, including safety in genetic level and ability to produce beneficial metabolites and extracellular polysaccharides. Ability of extensive carbon source utilization and short-chain fatty acid production was observed with single YY-26 cultivation. Considerable acetic acids and lactic acids were determined in GMPS utilization. YY-26 showed tolerance to simulated gastrointestinal tract and displayed appreciable antioxidant activity of free radical scavenging.

Conclusions: B. pseudolongum YY-26 was identified with numerous probiotic-associated genes and its probiotic characteristics were verified in vitro.

Significance and impact of study: This study supplemented with limited publicly information regarding the genomes of B. pseudolongum strains and revealed the probiotic potential of YY-26.