title: Inhibitory effects of the macrolide antimicrobial tylosin on anaerobic treatment.
abstract: A laboratory-scale anaerobic sequencing batch reactor (ASBR) was operated using a glucose-based synthetic wastewater to study the effects of tylosin, a macrolide antimicrobial commonly used in swine production, on treatment performance. The experimental period was divided into three consecutive phases with different influent tylosin concentrations (0, 1.67, and 167 mg/L). The addition of 1.67 mg/L tylosin to the reactor had negligible effects on the overall treatment performance, that is, total methane production and effluent chemical oxygen demand did not change significantly (P < 0.05), yet analyses of individual ASBR cycles revealed a decrease in the rates of both methane production and propionate uptake after tylosin was added. The addition of 167 mg/L tylosin to the reactor resulted in a gradual decrease in methane production and the accumulation of propionate and acetate. Subsequent inhibition of methanogenesis was attributed to a decrease in the pH of the reactor. After the addition of 167 mg/L tylosin to the reactor, an initial decrease in the rate of glucose uptake during the ASBR cycle followed by a gradual recovery was observed. In batch tests, the specific biogas production with the substrate butyrate was completely inhibited in the presence of tylosin. This study indicated that tylosin inhibited propionate- and butyrate-oxidizing syntrophic bacteria and fermenting bacteria resulting in unfavorable effects on methanogenesis.
authors.affiliation: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
authors.forename: Toshio
authors.initials: T
authors.lastname: Shimada
authors.forename: Julie L
authors.initials: JL
authors.lastname: Zilles
authors.forename: Eberhard
authors.initials: E
authors.lastname: Morgenroth
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Raskin
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000378:metabolism*; D018942:Macrolides / Q000008:administration & dosage; D008657:Metabolic Clearance Rate / Q000187:drug effects; D008697:Methane / Q000378:metabolism*; D015645:Tylosin / Q000008:administration & dosage*; D014874:Water Pollutants, Chemical / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides; D014874:Water Pollutants, Chemical; D005947:Glucose; D008697:Methane; D015645:Tylosin