show Abstracthide AbstractHere we explored the effect of two perturbations on the stability of a synthetic human gut bacterial community grown in microbioreactors in emulated chemostat mode. The (type)strains used were: Roseburia intestinalis (DSM 14610), Blautia hydrogenotrophica (DSM 10507), Bacteroides thetaiotaomicron (DSM 2079). We first applied a pH perturbation by decreasing the pH of the feed (WC with pH 6.4 to pH 3.38) between t97 and t109 (24 hours total). Subsequently, we applied a perturbation in the dilution rate by stopping the feed for 12 hours between t251 and t263 (periodic removal of liquid continued), after which an additional 5 mL fresh medium (50% of total volume) was added to the vessels.