Chronic impact of tetracycline on the biodegradation of an organic substrate mixture under anaerobic conditions

• Published in: Water research (Oxford) Vol. 47; no. 9; pp. 2959 - 2969
• Main Authors: Cetecioglu, Z., Ince, B., Gros, M., Rodriguez-Mozaz, S., Barceló, D., Orhon, D., Ince, O.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2013; Elsevier
• Subjects: Anaerobic biodegradation; anaerobic conditions; Anaerobiosis - drug effects; Applied sciences; Bacteria - drug effects; Bacteria - metabolism; Batch Cell Culture Techniques; bioavailability; biodegradation; Biodegradation, Environmental - drug effects; Biofuels - analysis; biogas; Biological Oxygen Demand Analysis; biomass; Bioreactors - microbiology; byproducts; Carbon Dioxide - analysis; chemical oxygen demand; Chronic inhibition; COD removal; Exact sciences and technology; Fatty Acids, Volatile - analysis; glucose; long term effects; methane; Methane - analysis; Methanogenesis; methanogens; microbial activity; microbial communities; Organic Chemicals - isolation & purification; Other wastewaters; Pollution; starch; Tetracycline; Tetracycline - chemistry; Tetracycline - pharmacology; volatile fatty acids; Wastewaters; Water treatment and pollution; Anaerobic biodegradation; Methanogenesis; Tetracycline; Chronic inhibition; COD removal; Removal; Microbial activity; Glucose; Mixture; Sequencing batch reactor; Anaerobe; Chemical oxygen demand; Volatile fatty acid; Inhibition; Microbial community; Biodegradation; Aldose; Starch; Pollutant behavior; Tetracycline derivatives; Substrate; Bioreactor; Antibiotic; Chronic; Emerging pollutant; Antibacterial agent
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2013.02.053

The study evaluates the chronic impact of the antibiotic tetracycline on the biodegradation of organic substrate under anaerobic conditions. The experiments involved an anaerobic sequencing batch reactor fed with a synthetic substrate mixture including glucose, starch and volatile fatty acids, and operated in a sequence of different phases with gradually increasing tetracycline doses of 1.65–8.5 mg/L, for more than five months. Tetracycline exerted a terminal/lethal effect at 8.5 mg/L on the microbial community under anaerobic conditions, which caused the inhibition of substrate/COD utilization and biogas generation and leading to a total collapse of the reactor. The microbial activity could not be recovered and re-started within a period of more than 10 days, even after stopping tetracycline dosing. At lower doses, substrate utilization was not affected but a reduction of 10–20% was observed in the biogas/methane generation, suggesting that substrate utilization of tetracycline to the biomass was limiting their bioavailability. During the experiments, tetracycline was partially removed either through biodegradation or conversion into its by-products. The adverse long-term impact was quite variable for fermenting heterotrophic and methanogenic fractions of the microbial community based on changes inflicted on the composition of remaining/residual organic substrate. •Chronic impact of tetracycline was lethal at 8.5 mg/L on the microbial community.•At lower doses, substrate removal was not impaired but biogas volume was reduced.•Tetracycline was partially biodegraded.•Impact was cumulative on fermenting heterotrophs due to TET adsorption/accumulation.•Impact was reversible for methanogens with partial recovery of biogas generation.