초록
<P><B>Abstract</B></P> <P>A dynamic membrane (DM) is a biofilm that forms on a support material, acting as a filter to retain high-density biomass. This study aims to explain the effects of alginate immobilization on DM formation during dark-H<SUB>2</SUB> fermentation. Galactose is used as a model substrate. Heat-treated anaerobic sludge, with and without immobilization, is used for an inoculum for two identical lab-scale DM bioreactors (DMBR). The DMBRs are continuously operated for more than 40 days by changing the hydraulic retention time (HRT) from 12 to 3 h. Biomass retention and H<SUB>2</SUB> production performance are significantly improved at an HRT of 3 h with immobilization. The alginate-added bioreactor shows higher extracellular polymeric substance content both in the mixed liquor and the DM. At an HRT of 3 h with immobilization, the fraction of <I>Sporolactobacillus</I> spp. and <I>Lactobacillus</I> spp. increases, possibly contributing to DM formation. However, lactic-acid concentration does not increase, implying it can be further consumed by the dominant bacteria, <I>Clostridium butyricum</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dynamic membrane (DM) was established in H<SUB>2</SUB> production from galactose. </LI> <LI> Inoculation with alginate facilitated DM formation and H<SUB>2</SUB> production. </LI> <LI> <I>Sporolactobacillus</I> and <I>Lactobacillus</I> increased along with the DM formation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>