title: Citric acid wastewater as electron donor for biological sulfate reduction.
abstract: Citrate-containing wastewater is used as electron donor for sulfate reduction in a biological treatment plant for the removal of sulfate. The pathway of citrate conversion coupled to sulfate reduction and the microorganisms involved were investigated. Citrate was not a direct electron donor for the sulfate-reducing bacteria. Instead, citrate was fermented to mainly acetate and formate. These fermentation products served as electron donors for the sulfate-reducing bacteria. Sulfate reduction activities of the reactor biomass with acetate and formate were sufficiently high to explain the sulfate reduction rates that are required for the process. Two citrate-fermenting bacteria were isolated. Strain R210 was closest related to Trichococcus pasteurii (99.5% ribosomal RNA (rRNA) gene sequence similarity). The closest relative of strain S101 was Veillonella montepellierensis with an rRNA gene sequence similarity of 96.7%. Both strains had a complementary substrate range.
authors.affiliation: Wageningen University, Dreijenplein, The Netherlands. fons.stams@wur.nl
authors.forename: Alfons J M
authors.initials: AJ
authors.lastname: Stams
authors.forename: Jacco
authors.initials: J
authors.lastname: Huisman
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Garcia Encina
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019343:Citric Acid / Q000737:chemistry / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D004583:Electrons; D005285:Fermentation; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D012722:Sewage / Q000382:microbiology; D013431:Sulfates / Q000737:chemistry / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012722:Sewage; D013431:Sulfates; D019343:Citric Acid