title: Selenium oxyanion inhibition of hydrogenotrophic and acetoclastic methanogenesis.
abstract: Inhibitory effects of selenite and selenate towards hydrogenotrophic and acetoclastic methanogenesis were evaluated in anaerobic toxicity assays. The 50% inhibitory concentration (IC50) of both selenium oxyanions was below 6.1x10(-5)M in hydrogenotrophic assays, whereas acetoclastic methanogens were less inhibited: IC50=8.3x10(-5)M and 5.5x10(-4)M for selenite and selenate, respectively. Selenite completely inhibits methanogenesis from both substrates tested at concentrations > or =10(-3)M selenite, while only marginal methanogenic activities occur at equimolar concentrations of selenate. Selenite becomes irreversibly inhibitory upon a single exposure, whereas selenate inhibits methanogens upon repeated exposure. Consequently, methane recovery can be seriously hampered or even impossible during anaerobic treatment of highly selenium contaminated waste streams.
authors.affiliation: Sub-Department of Environmental Technology, Wageningen University, 6700 EV Wageningen, The Netherlands.
authors.forename: Markus
authors.initials: M
authors.lastname: Lenz
authors.forename: Niklas
authors.initials: N
authors.lastname: Janzen
authors.forename: Piet N L
authors.initials: PN
authors.lastname: Lens
mesh_terms: D000693:Anaerobiosis; D000838:Anions; D006859:Hydrogen / Q000378:metabolism*; D008697:Methane / Q000096:biosynthesis*; D012643:Selenium / Q000737:chemistry / Q000494:pharmacology*; D012722:Sewage
chemical_list: D000838:Anions; D012722:Sewage; D006859:Hydrogen; D012643:Selenium; D008697:Methane