Why are you stressed? A systems-level comparison of two Bifidobacterium strains with different stability characteristics

Conference poster, 2021

Bifidobacteria are widely used as probiotics, owing to their well-documented health-promoting properties. Throughout production, downstream processing and administration, probiotic bifidobacteria are exposed to various stressors that may affect the physiological state of the cells. The stability of bifidobacteria varies between strains and the sensitivity of some strains hampers their industrial production. Therefore, it is crucial to gain a more comprehensive, systems-level understanding of their metabolism and physiology, which may result in the identification of potential factors and metabolic bottlenecks influencing both growth and long-term viability. In this work, we compare the metabolic characteristics of two industrially relevant bifidobacterial strains that vary in their stability. Our approach relies on the integration of different phenotypic measurements using a constraint-based metabolic modelling framework. In order to identify the correlation between cellular characteristics and stability, the strains were studied in lab-scale pH-controlled fermentations in chemically-defined medium and their final stability was assessed. The cultivations were monitored by assessing growth and metabolite production. In addition, global transcriptome profiling and differential gene expression analysis were used to gain better insights into the metabolic differences between the strains. The genome-scale metabolic models of the strains were used as platforms for the integration of experimental data.