Methanogens, sulphate and heavy metals: a complex system

L. Da Luz Ferreira Martins Paulo, A.J.M. Stams, D.Z. Machado de Sousa*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

90 Citations (Scopus)


Anaerobic digestion (AD) is a well-established technology used for the treatment of wastes and wastewaters with high organic content. During AD organic matter is converted stepwise to methane-containing biogas—a renewable energy carrier. Methane production occurs in the last AD step and relies on methanogens, which are rather sensitive to some contaminants commonly found in wastewaters (e.g. heavy metals), or easily outcompeted by other groups of microorganisms (e.g. sulphate reducing bacteria, SRB). This review gives an overview of previous research and pilot-scale studies that shed some light on the effects of sulphate and heavy metals on methanogenesis. Despite the numerous studies on this subject, comparison is not always possible due to differences in the experimental conditions used and parameters explained. An overview of the possible benefits of methanogens and SRB co-habitation is also covered. Small amounts of sulphide produced by SRB can precipitate with metals, neutralising the negative effects of sulphide accumulation and free heavy metals on methanogenesis. Knowledge on how to untangle and balance sulphate reduction and methanogenesis is crucial to take advantage of the potential for the utilisation of biogenic sulphide as a metal detoxification agent with minimal loss in methane production in anaerobic digesters.
Original languageEnglish
Pages (from-to)537-553
JournalReviews in Environmental Science & Bio-technology
Issue number4
Publication statusPublished - Dec 2015


  • Heavy metals
  • Inhibition
  • Methanogenesis
  • Sulphate reducers
  • Sulphide
  • Syntrophy


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