Effects of oxytetracycline on mesophilic and thermophilic anaerobic digestion for biogas production from swine manure.

• Swine manure anaerobic digestion (AD) at 55 °C raised 47.9% methane than at 35 °C. • More oxytetracycline (OTC) led to less methane from mesophilic and thermophilic ADs. • Adding 400 mg/L OTC reduced energy conversion efficiencies of ADs by 21.4–48.4%. • More than 63.0% and 72.5% OTC were removed via mesophilic and thermophilic ADs. • Methanolinea was bearable to high content OTC in mesophilic and thermophilic ADs. Anaerobic digestion (AD) technology is a valuable method for producing biogas fuels and treating livestock wastes such as swine manures concurrently. However, the effect of emerging antibiotics on the AD process is still undiscovered. In this study, the influence of oxytetracycline (OTC) on the AD process was investigated under mesophilic (35 ± 0.5 °C) and thermophilic (55 ± 0.5 °C) conditions, respectively. The presence of OTC significantly inhibited the production of methane in AD process, where the methane yields decreased by 58.6% and 73.3% in mesophilic and thermophilic ADs when the initial concentration of OTC was 400 mg/L, respectively. Besides, OTC can be markedly degraded by the AD process with a removal efficiency higher than 90% when the OTC initial concentration is lower than 10 mg/L. Furthermore, a higher concentration OTC led to a lower biomethane yield, energy conversion efficiency, and contaminant removal during both mesophilic and thermophilic ADs. With adding of 400 mg/L OTC, Clostridium sensu stricto 1 (32.9%) and Anaerolinea (29.3%) are dominant to biodegrade organic matter during mesophilic and thermophilic AD systems. Correspondingly, Methanosaeta was functional in producing biomethane in both mesophilic (60.8%) and thermophilic (56.4%) AD systems. Additionally, Methanolinea was bearable to high concentrations of OTC during mesophilic and thermophilic AD processes. [ABSTRACT FROM AUTHOR]