title: Effect of cobalt on the anaerobic thermophilic conversion of methanol.
abstract: The importance of cobalt on the anaerobic conversion of methanol under thermophilic conditions was studied in three parallel lab-scale UASB-reactors and in cobalt-limited enriched cultures. Reactors R1, R2, and R3 were fed with methanol in a bicarbonate-buffered medium, supplied with iron and macronutrients: in R1 all metals were supplied (control), R2 was cobalt deprived, and in R3 all metals were deprived. In the 136 days of continuous experiment, a drop in performance was observed over the last 30 days. Particularly in R3, both methanol removal and methane formation dropped by 7.1% and 13.7%, respectively, compared to the control reactor, R1. When the medium was cobalt-deprived, acetate was not produced and, as a consequence, the enriched consortium lost its capacity to degrade acetate, indicating that the acetotrophic microorganisms were washed out. The addition of 0.5 microM of cobalt to a cobalt-deprived enrichment culture led to acetate accumulation. The results obtained in this study indicate that the mixed consortium requires a proper amount of cobalt, and its addition to a concentration of 0.1 microM leads to the highest methanol conversion rate, with methane as the sole end product from methanol.
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, Bomenweg 2, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands. paula.paulo@wur.nl
authors.forename: Paula L
authors.initials: PL
authors.lastname: Paulo
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.forename: Denise
authors.initials: D
authors.lastname: Cysneiros
authors.forename: Alfons J M
authors.initials: AJ
authors.lastname: Stams
authors.forename: Gatze
authors.initials: G
authors.lastname: Lettinga
mesh_terms: D000085:Acetates / Q000378:metabolism; D001421:Bacteria, Anaerobic / Q000187:drug effects* / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D003035:Cobalt / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D019605:Euryarchaeota / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D008697:Methane / Q000378:metabolism; D000432:Methanol / Q000378:metabolism*; D012722:Sewage
chemical_list: D000085:Acetates; D012722:Sewage; D003035:Cobalt; D008697:Methane; D000432:Methanol