Anaerobic bio-hydrogen production from ethanol fermentation: The role of pH

Moon H. Hwang, Nam J. Jang, Seung H. Hyun, In S. Kim

Research output: Contribution to journalArticlepeer-review

271 Citations (Scopus)


Hydrogen was produced by an ethanol-acetate fermentation at pH of 5.0 ± 0.2 and HRT of 3 days. The yield of hydrogen was 100-200 ml g Glu -1 with a hydrogen content of 25-40%. This fluctuation in the hydrogen yield was attributed to the formation of propionate and the activity of hydrogen utilizing methanogens. The change in the operational pH for the inhibition of this methanogenic activity induced a change in the main fermentation pathway. In this study, the main products were butyrate, ethanol and propionate, in the pH ranges 4.0-4.5, 4.5-5.0 and 5.0-6.0, respectively. However, the activity of all the microorganisms was inhibited below pH 4.0. Therefore, pH 4.0 was regarded as the operational limit for the anaerobic bio-hydrogen production process. These results indicate that the pH plays an important role in determining the type of anaerobic fermentation pathway in anaerobic bio-hydrogen processes.

Original languageEnglish
Pages (from-to)297-309
Number of pages13
JournalJournal of Biotechnology
Issue number3
Publication statusPublished - 2004 Aug 5
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by Korea Energy Management Corporation (KEMCO) and Advanced Environmental Monitoring Research Center (ADEMRC).


  • Anaerobic bio-hydrogen production
  • Ethanol-acetate fermentation
  • Methanogenic activity
  • pH effect

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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