This study investigated the kinetic parameters of high-rate continuous performance and biofilm layer formation in a H-2-producing dynamic membrane bioreactor, composed of a continuously stirred tank reactor along with an external module containing polyester mesh with a pore size of 100 mu m. A maximum H-2 production rate of 48.9 L/L-day and hydrogen yield of 2.8 mol/mol glucoseadded were attained at a hydraulic retention time of 3 h. The maximum specific growth rate and Monod constant were estimated as 14.92 d(-1) and 1.02 g COD/L, respectively. During the entire operation without backwashing, the transmembrane pressure remained below 1.7 kPa, while tightly bound extracellular polymeric substances increased as the dynamic membrane was developed. Fluorescent in situ hybridization and quantitative polymerase chain reaction assays revealed that Clostridium butyricum was dominant in all samples; however, the biofilm had a higher proportion of Prevotella spp. than the fermentation liquor.