High tolerance of methanogens in granular sludge to oxygen

Mario T. Kato, Jim A. Field, Gatze Lettinga

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


This research assessed the effect of oxygen exposure on the methanogenic activity of anaerobic granular sludges. The toxicity of oxygen to acetoclastic methanogens in five different anaerobic granular sludges was determined in serum flasks with effective gas‐to‐liquid volumes of 4.65 to 1. The amount of oxygen that caused 50% inhibition of the methanogenic activity after 3 days of exposure ranged from 7% to 41% oxygen in the head space. These results indicate that methanogens located in granular sludge have a high tolerance for oxygen. The most important factor contributing to the tolerance was the oxygen consumption by facultative bacteria metabolizing biodegradable substrates. Uptake of oxygen by these bacteria creates anaerobic microenvironments where the methanogenic bacteria are protected. The results also indicate that methanogens in sludge consortia still have some tolerance to oxygen, even in the absence of facultative substrate for oxygen respiration. © 1993 John Wiley & Sons, Inc.

Original languageEnglish (US)
Pages (from-to)1360-1366
Number of pages7
JournalBiotechnology and Bioengineering
Issue number11
StatePublished - Dec 1993


  • anaerobic biofilm
  • facultative and methanogenic bacteria
  • oxygen toxicity
  • wastewater treatment

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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