Inhibition of biomethane production under antibiotics in poultry litter

Anaerobiosis is a well-established biotechnology which treats animal manure for methanogenesis. The presence of various antibiotics in poultry waste may inhibit anaerobic digestion (AD). The current study aimed at investigating the effects of various antibiotics on the AD of poultry litter. The batch experiments were performed with an inoculum/substrate ratio of 1 in sealed glass vials incubated under anaerobic conditions at 37 °C for 21 days. The antibiotics, i.e., bacitracin (BAC), erythromycin (ERY), monensin (MON), and tetracycline (TET), were added at the concentration ranges of 0.02 to 0.1 mg mL⁻¹. During the first week, the inhibitory effects of monensin were higher (36–60%) as compared with other antibiotics. For 8–15 days and 16–21 days, the inhibitory effects caused by erythromycin were 28–38%, followed by 21–35% of TET and 20–40% of BAC. MON showed lower inhibition during the final stages of experiment which might possibly be due to its biodegradation.