Segatella copri is a key member of the human gut microbiome and its strain-level diversity is well described in several studies indicating different metabolic capabilities and positive effects on the host. The species is described as a possible next-generation probiotic, which either requires a well-stimulated in vivo establishment or an additional supplementation as actively growing culture. The latter requires oxygen-tolerance of these strict anaerobic bacteria as during the application oxygen exposure cannot be excluded as well as passage through the gastrointestinal tract will yield in different oxygen exposure conditions. There is still a lack of knowledge on how S. copri can cope with even small oxygen concentrations and which enzymes are involved in the counteraction of cell damage due to oxygen stress. The genome of S. copri contains genes for terminal oxidases and peroxidases but no genes for superoxide dismutases or catalases are annotated. We hypothesize that S. copri response to oxygen stress by nanaerobic respiration and by oxidation of thiols. In our collaborative project, we aim at identifying the genetic repertoire and the enzymatic reactions acting against oxidative stress at all biological levels in the cell, comparing the transcriptome, proteome and metabolome of S. copri reference strains with and without exposure to stressors. This will be approved by mutant strains lacking ROS-protective components and enzymes. Understanding these mechanisms will be crucial to enhance the survival of S. copri during future applications as a probiotic strain. This can prevent possible selection mechanisms during oxygen exposure in the gastrointestinal tract which might lead to negative effects on the host.