Biohydrogen production in granular up-flow anaerobic sludge blanket (UASB) reactors with mixed cultures under hyper-thermophilic temperature (70°C)

Hyper‐thermophilic hydrogen production without methane was demonstrated for the first time in granular up‐flow anaerobic sludge blanket (UASB) system fed with glucose using mixed cultures. The maximum hydrogen yield in this study was 2.47 ± 0.15 mol H2/mol glucose. This high yield has never been previously reported in mixed culture systems and it was likely due to more favorable thermodynamic conditions at hyper‐thermophilic temperatures. Different start‐up strategies (bromoethanosulfonate (BES) addition and flow recycle) were evaluated. BES addition during start‐up prevented the establishment of methanogenic cultures in granules. Flow recycle was important to achieve higher hydrogen yield through enriching better hydrogen‐producing organisms and reduced the start‐up period as well. This study indicated UASB system was a promising system for hydrogen production. © 2006 Wiley Periodicals, Inc.