Hydrogen production with effluent from an ethanol-H2-coproducing fermentation reactor using a single-chamber microbial electrolysis cell

Lu Lu, Nanqi Ren, Defeng Xing, Bruce E. Logan

Research output: Contribution to journalArticlepeer-review

135 Scopus citations


Hydrogen can be produced by bacterial fermentation of sugars, but substrate conversion to hydrogen is incomplete. Using a single-chamber microbial electrolysis cell (MEC), we show that additional hydrogen can be produced from the effluent of an ethanol-type dark-fermentation reactor. An overall hydrogen recovery of 83 ± 4% was obtained using a buffered effluent (pH 6.7-7.0), with a hydrogen production rate of 1.41 ± 0.08 m3 H2/m3 reactor/d, at an applied voltage of Eap = 0.6 V. When the MEC was combined with the fermentation system, the overall hydrogen recovery was 96%, with a production rate of 2.11 m3 H2/m3/d, corresponding to an electrical energy efficiency of 287%. High cathodic hydrogen recoveries (70 ± 5% to 94 ± 4%) were obtained at applied voltages of 0.5-0.8 V due to shorter cycle times, and repression of methanogen growth through exposure of the cathode to air after each cycle. Addition of a buffer to the fermentation effluent was critical to MEC performance as there was little hydrogen production using unbuffered effluent (0.0372 m3 H2/m3/d at Eap = 0.6 V, pH 4.5-4.6). These results demonstrate that hydrogen yields from fermentation can be substantially increased by using MECs.

Original languageEnglish (US)
Pages (from-to)3055-3060
Number of pages6
JournalBiosensors and Bioelectronics
Issue number10
StatePublished - Jun 15 2009

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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