Formation of a dynamic membrane altered the microbial community and metabolic flux in fermentative hydrogen production

This study aimed to investigate the relationship among dynamic membrane (DM) formation, metabolic flux, and microbial community population in dark fermentative hydrogen production. A continuously stirred tank reactor was equipped with an external submerged polyester screen mesh and inoculated with heat-treated anaerobic sludge without immobilization. DM was successfully developed on the polyester mesh and provided high-rate hydrogen production at 60.5 L H-2/L.d and 2.39 mol H-2/mol glucose(added). DM formation was along with tightly bound extracellular polymeric substances. Flux balance analysis revealed that formation of DM altered the metabolic pathways for acetic acid production from homoacetogenesis to hydrogenesis. Bacterial community analysis suggested that Sporolactobacillaceae would contributed to this metabolic pathway shift. Nevertheless, lactic acid was not accumulated and assumed to be consumed by hydrogen producers including Clostridia.