Open AccessEffect of 2‐bromo‐ethane sulfonate, molybdate and chloroform on acetate consumption by methanogenic and sulfate‐reducing populations in freshwater sediment
Author(s) -
Scholten Johannes C.M.,
Conrad R.,
Stams Alfons J.M.
Publication year - 2000
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2000.tb00696.x
Subject(s) - methanogenesis , sulfate , propionate , sulfate reducing bacteria , acetogenesis , biology , chloroform , valerate , environmental chemistry , butyrate , inorganic chemistry , biochemistry , chemistry , methane , organic chemistry , ecology , fermentation
The relative importance of methanogenesis and sulfate reduction in freshwater sediment supplemented with acetate was investigated. Addition of acetate stimulated both methane formation and sulfate reduction, indicating that an active aceticlastic population of methanogens and sulfate reducers was present in the sediment. Sulfate reducers were most important in the consumption of acetate. However, when sulfate reducers were inhibited, acetate was metabolised at a similar rate by methanogens. Acetate, propionate and valerate accumulated only when both processes were inhibited by the combined addition of 2‐bromo‐ethane sulfonate and molybdate. The relative amounts of acetate, propionate and valerate were 93, 6 and 1 mol%, respectively. These results demonstrate the role of acetate as a key intermediate in the terminal step of organic matter mineralisation in the sediment. Addition of chloroform inhibited both methanogenesis and sulfate reduction. We studied the inhibitory effect of CHCl 3 on homoacetogenic bacteria, sulfate‐reducing bacteria and methanogens. The results showed that inhibition by CHCl 3 correlates with microorganisms, which operate the acetyl‐CoA cleavage pathway. We propose that chloroform can be used to elucidate the role of different metabolic types of sulfate reducers to sulfate reduction in natural environments.