Effect of sulfate and nitrate on acetate conversion by anaerobic microorganisms in a freshwater sediment

• Published in: FEMS microbiology ecology Vol. 42; no. 3; pp. 375 - 385
• Main Authors: Scholten, Johannes C.M., van Bodegom, Peter M., Vogelaar, Jaap, van Ittersum, Alexander, Hordijk, Kees, Roelofsen, Wim, Stams, Alfons J.M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.2002; Blackwell; Oxford University Press
• Subjects: acetaten; acetates; Acetic acid; Anaerobic microorganisms; Animal, plant and microbial ecology; Bacteria; bacteriën; Biodegradation of pollutants; Biological and medical sciences; Biotechnology; Competition; Conversion; denitrificatie; Denitrification; Denitrifying bacteria; Ecology; Environment and pollution; fresh water; Freshwater microorganisms; Fundamental and applied biological sciences. Psychology; Hydrologie; Hydrology; Industrial applications and implications. Economical aspects; Inhibition; Low concentrations; methaan; methaanproductie; methane; methane production; Methanogenesis; Methanogenic bacteria; Microbial ecology; Microbiology; Microorganisms; Most‐probable‐number enumeration; Nitrates; remming; sediment; Sediments; Substrates; Sulfate reduction; Sulfates; Sulfides; Various environments (extraatmospheric space, air, water); zoet water; Netherlands; Europe; Competition; Sulfate reduction; Denitrification; Inhibition; Methanogenesis; Most-probable-number enumeration; Freshwater environment; Methane; Substrate; Anaerobe; Methanogenic bacteria; Nitrates; Acetate; Microorganism; Sulfates; Sediments; Conversion; Electron acceptor
• ISSN: 0168-6496; 1574-6941
• DOI: 10.1111/j.1574-6941.2002.tb01027.x

Abstract Acetate is quantitatively the most important substrate for methane production in a freshwater sediment in The Netherlands. In the presence of alternative electron acceptors the conversion of acetate by methanogens was strongly inhibited. By modelling the results, obtained in experiments with and without 13C-labelled acetate, we could show that the competition for acetate between methanogens and sulfate reducers is the main cause of inhibition of methanogenesis in the sediment. Although nitrate led to a complete inhibition of methanogenesis, acetate-utilising nitrate-reducing bacteria hardly competed with methanogens for the available acetate in the presence of nitrate. Most-probable-number enumerations showed that methanogens (2×108 cells cm−3 sediment) and sulfate reducers (2×108 cells cm−3 sediment) were the dominant acetate-utilising organisms in the sediment, while numbers of acetate-utilising nitrate reducers were very low (5×105 cells cm−3 sediment). However, high numbers of sulfide-oxidising nitrate reducers were detected. Denitrification might result in the formation of toxic products. We speculate that the accumulation of low concentrations of NO (<0.2 mM) may result in an inhibition of methanogenesis.