Biohydrogen production from glucose, molasses and cheese whey by suspended and attached cells of four hyperthermophilic Thermotoga strains

BACKGROUND: Bio‐hydrogen production from organic residues is an attractive process that combines energy generation with waste treatment. This work describes hydrogen production from molasses and cheese whey by biofilm and suspended‐cells of four hyperthermophilic Thermotoga spp. For the best performing strain, a preliminary process optimization was performed. RESULTS: In experiments with glucose‐fed T. neapolitana , HEPES was the best‐performing buffer, whereas the highest H 2 rate was obtained with the biofilm support exposing the highest specific surface. All the Thermotoga strains tested ( T. neapolitana, T. maritima, T. naphtophila, T. petrophila ) were able to produce H 2 from glucose, molasses and cheese whey under both suspended‐ and attached‐cell conditions. T. neapolitana was the best H 2 producer with all three substrates. The best H 2 production rate was higher on molasses (1.7 mmol H2 L $_{\rm {medium}}^{-1}$ h −1 ) than on cheese whey (0.94 mmol H2 L $_{\rm {medium}}^{-1}$ h −1 ), whereas the highest H 2 /substrate yields were similar for the two substrates (2.95 mol H2 mol $_{\rm {monosaccharide consumed}}^{-1}$ on molasses and 2.50 mol H2 mol $_{\rm {monosaccharide consumed}}^{-1}$ on cheese whey). With both wastes, the progressive growth medium simplification allowed a drastic reduction of medium cost, without significant losses of process performance. CONCLUSION: Both molasses and cheese whey are suitable substrates for H 2 production by suspended‐ and attached‐cells of Thermotoga species. Copyright © 2012 Society of Chemical Industry