title: Specific inhibitors for identifying pathways for methane production from carbon monoxide by a nonadapted anaerobic mixed culture.
abstract: Specific inhibitors such as 2-bromoethanesulfonate (BES) and vancomycin were employed in activity batch tests to decipher metabolic pathways that are preferentially used by a mixed anaerobic consortium (sludge from an anaerobic digester) to transform carbon monoxide (CO) into methane (CH4). We first evaluated the inhibitory effect of both BES and vancomycin on the microbial community, as well as the efficiency and stability of vancomycin at 35 °C, over time. The activity tests with CO2-H2, CO, glucose, acetate, formate, propionate, butyrate, methanol, and ethanol showed that vancomycin does not inhibit some Gram-negative bacteria, and 50 mmol/L BES effectively blocks CH4 production in the sludge. However, when sludge was incubated with propionate, butyrate, methanol, or ethanol as the sole energy and carbon source, methanogenesis was only partially inhibited by BES. Separate tests showed that 0.07 mmol/L vancomycin is enough to maintain its inhibitory efficiency and stability in the population for at least 32 days at 35 °C. Using the inhibitors above, it was demonstrated that CO conversion to CH4 is an indirect, 2-step process, in which the CO is converted first to acetate and subsequently to CH4.
authors.affiliation: a Bioengineering Group, Energy, Mining and Environment, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada.
authors.forename: Silvia Sancho
authors.initials: SS
authors.lastname: Navarro
authors.forename: Ruxandra
authors.initials: R
authors.lastname: Cimpoia
authors.forename: Guillaume
authors.initials: G
authors.lastname: Bruant
authors.forename: Serge R
authors.initials: SR
authors.lastname: Guiot
mesh_terms: D000085:Acetates / Q000378:metabolism; D017738:Alkanesulfonic Acids / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001105:Archaea / Q000187:drug effects / Q000378:metabolism; D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002248:Carbon Monoxide / Q000378:metabolism*; D005561:Formates / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D008697:Methane / Q000378:metabolism*; D011422:Propionates / Q000378:metabolism; D012722:Sewage / Q000382:microbiology; D014640:Vancomycin / Q000494:pharmacology*; D020713:Vancomycin Resistance / Q000235:genetics
chemical_list: D000085:Acetates; D017738:Alkanesulfonic Acids; D000900:Anti-Bacterial Agents; D005561:Formates; D011422:Propionates; D012722:Sewage; C030544:formic acid; D002245:Carbon Dioxide; C018853:2-bromoethanesulfonic acid; D014640:Vancomycin; D002248:Carbon Monoxide; D005947:Glucose; D008697:Methane
keywords: anaerobic; anaérobie; bromoethanesulfonate (BES); bromoéthanesulfonate (BES); carbon monoxide; carboxydotrophie; carboxydotrophy; methanation; methanogenesis; monoxyde de carbone; méthanation; méthanogénèse; vancomycin; vancomycine