Open AccessMethanogenic biodegradation of two‐ringed polycyclic aromatic hydrocarbons
Author(s) -
BerdugoClavijo Carolina,
Dong Xiaoli,
Soh Jung,
Sensen Christoph W.,
Gieg Lisa M.
Publication year - 2012
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.1574-6941.2012.01328.x
Subject(s) - biodegradation , methanogenesis , naphthalene , environmental chemistry , methane , polycyclic aromatic hydrocarbon , enrichment culture , biology , metabolite , hydrocarbon , methanosaeta , microbial biodegradation , organic chemistry , bacteria , chemistry , microorganism , biochemistry , ecology , genetics
Polycyclic aromatic hydrocarbons ( PAH ) are widespread in methane‐rich subsurface environments, such as oil reservoirs and fuel‐contaminated aquifers; however, little is known about the biodegradation of these compounds under methanogenic conditions. To assess the metabolism of PAH in the absence of electron acceptors, a crude oil‐degrading methanogenic enrichment culture was tested for the ability to biodegrade naphthalene, 1‐methylnaphthalene (1‐ MN ), 2‐methylnaphthalene (2‐ MN ), and 2, 6‐dimethylnaphthalene (2, 6‐di MN ). When methane was measured as an indicator of metabolism, nearly 400 μmol of methane was produced in the 2‐ MN ‐ and 2, 6‐di MN ‐amended cultures relative to substrate‐unamended controls, which is close to the amount of methane stoichiometrically predicted based on the amount of substrate added (51–56 μmol). In contrast, no substantial methane was produced in the naphthalene‐ and 1‐ MN ‐amended enrichments. In time course experiments, metabolite analysis of enrichments containing 2‐ MN and 2, 6‐di MN revealed the formation of 2‐naphthoic acid and 6‐methyl‐2‐naphthoic acid, respectively. Microbial community analysis by 454 pyrosequencing revealed that these PAH ‐utilizing enrichments were dominated by archaeal members most closely affiliated with M ethanosaeta and M ethanoculleus species and bacterial members most closely related to the C lostridiaceae , suggesting that these organisms play an important role in the methanogenic metabolism of the substituted naphthalenes in these cultures.