Comparative analysis of hydrogen-producing bacterial biofilms and granular sludge formed in continuous cultures of fermentative bacteria

► An efficient system for biohydrogen production was presented. ► A high hydrogen yield of 5.43 mol H2/mol sucrose was achieved. ► 454-Pyrosequencing was used to analyze hydrogen-producing microbial communities. ► The relationship between bacterial consortium structure and the efficiency of hydrogen production was shown.