Small intestinal microbiota communities developed in vitro and the effect of oxygen

Taking advantage of the flexibility and control only attained through application of an in vitro platform, we were able develop a model of small intestinal gut microbiota that we used to address both the lack in knowledge regarding inter-subject variability and the communities response to physiological levels of O2. Here, we demonstrated that the composition of the inocula was the primary driver of inter-subject variability in structure and the resulting function, and that these were independent of the presence or absence of O2. Despite high levels of inter-subject variability, there was an observed lack of bile acid conversion from primary to secondary forms, which was not affected by the presence of O2. However, deconjugation of bile acids was dependent, at least in part, on the presence of O2. These results provide evidence that community structure of the small intestinal microbiota is not the only factor dictating the lack of bile acid metabolism, but that it is also contingent on the physiological environment and presence of O2. This is a novel finding that is important for bile acid functionality that is relevant to digestive physiology.