Biotransformation and biodegradation of N-substituted aromatics in methanogenic granular sludge

Elías Razo-Flores, Brian Donlon, Gatze Lettinga, Jim A. Field

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


N-Substituted aromatic compounds are environmental contaminants associated with the production and use of dyes, explosives, pesticides and pharmaceuticals. In this article, we examine the potential of anaerobic granular sludge from anaerobic treatment systems towards the detoxification, transformation, and mineralization of nitroaromatic and azo compounds, Nitroaromatics and azo dyes with strong electron withdrawing are highly inhibitory to acetoclastic methanogenic bacteria. However, nitro and azo substituted aromatics are readily reductively detoxified in methanogenic consortia to their respective aromatic amines, which are several orders of magnitude less toxic. This reductive detoxification has allowed the successful operation of anaerobic reactors for the treatment of highly toxic aromatic compounds. In the course of the experiments it was discovered that some aromatic airlines were mineralized. These results indicate that some N- substituted aromatic compounds can be completely mineralized and serve as a carbon and energy source for anaerobic bacteria.

Original languageEnglish (US)
Pages (from-to)525-538
Number of pages14
JournalFEMS Microbiology Reviews
Issue number3-4
StatePublished - Jul 1997


  • Anaerobic biodegradation
  • Anaerobic biotransforrnation
  • Anaerobic granular sludge
  • Aromatic amine
  • Azo dye
  • Nitroaromatic

ASJC Scopus subject areas

  • Microbiology
  • Infectious Diseases


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