<em>In vitro</em> fermentation mediated by <em>Akkermansia</em> <em>muciniphila</em>caused lactate accumulation and blocked butyrate production via shaping functional bacterial community

To research the effect of <em>Akkermansia muciniphila</em> on hypertension, we performed an <em>in vitro</em> fermentation on the feces of hypertensive patients. The experimental groups were hypertensive elderly (E), hypertensive elderly+<em>A. muciniphila</em> (EA), and hypertensive long-lived elderly (L). The pH value decreased among the three groups and produced numerous lactate at 9 h. Then, the pH value increased and lactate was almost exhausted at 48 h in group E. However,compared to groups E and L, group EA showed lower pH value, lower butyrate level, and higher lactate level. Compared to group E in 9 h, EA significantly increased the relative abundance of <em>Akkermansia </em>and <em>Lactococcus </em>and decreased <em>Clostridium_sensu_stricto_1</em>. The relative abundances of <em>Akkermansia </em>and <em>Bifidobacterium</em> increased in the EA compared to E, whereas the relative abundances of <em>Clostridium_sensu_stricto_1 </em>decreased at 48 h. Metabolomics showed that <em>A. muciniphila</em> altered the levels of 9 metabolites with reduced trimethylamine (TMA) and trimethyl-5-aminovaleric acid (TMAVA) related to hypertension. The lactate concentration showed positive correlation with <em>Enterococcus</em> and <em>Bifidobacterium</em>, and the butyrate concentration showed positive correlation with <em>Clostridium_sensu_stricto_1</em>, indicating that metabolites shifts by those functional bacterial communities. These results present a potential perspective for <em>A. muciniphila</em> mediated microbial micro-environment change to increase the relative abundance of <em>Bifidobacterium</em> and lactate production.