High-rate continuous hydrogen production by Thermoanaerobacterium thermosaccharolyticum PSU-2 immobilized on heat-pretreated methanogenic granules

Biohydrogen production from Thermoanaerobacterium thermosaccharolyticum strain PSU-2 was examined in upflow anaerobic sludge blanket (UASB) reactor and carrier-free upflow anaerobic reactor (UA), both fed with sucrose and operating at 60 °C. Heat-pretreated methanogenic granules were used as carrier to immobilize T. thermosaccharolyticum strain PSU-2 in UASB reactor operated at a hydraulic retention time (HRT) ranging from 0.75 to 24 h and corresponding sucrose loading rate from 58.5 to 2.4 mmol sucrose l−1 h−1. In comparison with hydrogen production rate of 12.1 mmol H2 l−1 h−1 obtained by carrier-free reactor upflow anaerobic (UA) system, a greatly improved hydrogen production rate up to 152 mmol H2 l−1 h−1 was demonstrated by the granular cells in UASB system. The biofilm of T. thermosaccharolyticum strain PSU-2 developed on treated methanogenic granules in UASB reactor substantially enhanced biomass retention (3 times), and production of hydrogen (12 times) compared to carrier-free reactor. It appears to be the most preferred process for highly efficient dark fermentative hydrogen production from sugar containing wastewater under thermophilic conditions.