[Inhibition of methanogenium by erythromycin and its domestation]

Erythromycin is a kind of antibiotic drugs with certain biological toxicity. In order to investigate the inhibitory effect of erythromycin on methanogens and its acclimation capacity, Anaerobic Toxicity Assay (ATA) and continuous experiment were conducted in anaerobic bottles and the Up-flow Anaerobic Sludge Blanket Reactor (UASB), respectively, to determine the accumulated methane production, ratio of methane production rate, COD removal efficiency, and methane content. The results showed that the methane production ratio was reduced to 56.1% in the presence of 150 mg x L(-1) of erythromycin and it was reduced by 99% when the erythromycin reached 250 mg x L(-1), indicating that the activity was completely inhibited. Keeping the erythromycin at an concentration of 20 mg x L(-1) in the process of continuous operation for 60d, the COD removal efficiency and methane content reached up to 81.4% and 64.2%, respectively. The results suggested that erythromycin had an inhibitory effect on methane bacteria, and the half inhibitory concentration was 150 mg x L(-1) (IC50:150 mg x L(-1)). The COD removal efficiency and methane content were increased by 15.13% and 22.05%, respectively, after domestication for 60 d.