Biodegradation of selected azo dyes under methanogenic conditions

Elías Razo-Flores, Maurice Luijten, Brian Donlon, Gatze Lettinga, Jim Field

Research output: Contribution to journalConference articlepeer-review

189 Scopus citations


Biological treatment of wastewaters discharged by the textile industry could potentially be problematic due to the high toxicity and recalcitrance of the commonly-used azo dye compounds. In the present report, the fate of two azo dyes under methanogenic conditions was studied. Mordant Orange 1 (MO1) and Azodisalicylate (ADS) were completely reduced and decolorised in continuous UASB reactors in the presence of cosubstrates. In the MO1 reactor, both 5-aminosalicylic acid (5-ASA) and 1,4-phenylenediamine were identified as products of azo cleavage. After long adaptation periods, 5-ASA was detected at trace levels, indicating further mineralization. ADS, a pharmaceutical azo dye constructed from two 5-ASA units, was completely mineralized even in the absence of cosubstrate, indicating that the metabolism of 5-ASA could provide the reducing equivalents needed for the azo reduction. Batch experiments confirmed the ADS mineralization. These results demonstrate that some azo dyes could serve as a carbon, energy, and nitrogen source for anaerobic bacteria.

Original languageEnglish (US)
Pages (from-to)65-72
Number of pages8
JournalWater Science and Technology
Issue number6-7
StatePublished - 1997
EventProceedings of the 1997 8th IAWQ International Conference on Anaerobic Digestion - Sendai, Jpn
Duration: May 25 1997May 29 1997


  • Anaerobic degradation
  • Azo dyes
  • Azodisalicylate
  • Granular sludge
  • Methanogenic conditions
  • Mordant Orange 1
  • UASB reactor

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology


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