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Keywords:

  • bio-hydrogen;
  • anaerobic digestion;
  • waste treatment and waste minimization;
  • process optimization;
  • Thermotoga;
  • biofilm carrier

Abstract

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 H2 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 H2 from glucose, molasses and cheese whey under both suspended- and attached-cell conditions. T. neapolitana was the best H2 producer with all three substrates. The best H2 production rate was higher on molasses (1.7 mmolH2 Lequation image h−1) than on cheese whey (0.94 mmolH2 Lequation image h−1), whereas the highest H2/substrate yields were similar for the two substrates (2.95 molH2 molequation image on molasses and 2.50 molH2 molequation image 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 H2 production by suspended- and attached-cells of Thermotoga species. Copyright © 2012 Society of Chemical Industry