Microbial community structures and antibiotic biodegradation characteristics during anaerobic digestion of chicken manure containing residual enrofloxacin

To explore the interaction between the residual antibiotic in animal manure and biological treatment, the effect of enrofloxacin (ENR) on the anaerobic digestion of chicken manure, and biodegradation rate of ENR was studied under the condition of actual residual ENR content of 0, 8, 16 and 32 mg/kg center dot TS. The results showed that the addition of ENR increased the total biogas production, especially 8 mg/kg center dot TS promoted the anaerobic reaction obviously, and the corresponding cumulative biogas production was increased by 15.33%. However, in the presence of 32 mg/kg center dot TS, the biogas production rate was reduced and the peak period of biogas production was delayed. The results of enzyme activities determination and 16S rRNA sequencing showed that ENR had different effects on archaea and bacteria. The residual ENR could promote hydrolysis reactions in the anaerobic system, but could inhibit acetoclastic methanogens, and the relative abundance of Methanosaeta declined by 7.22-12.41%. The first-order kinetic model showed that the half-life period of ENR in the anaerobic digestion system was 9.16-10.83 days, and the biodegradation rate exceeded 80% after the treatment. This study can bring important information for the management of animal manure in the future.

Automated summary

This study investigated the effect of residual enrofloxacin (ENR) on the anaerobic digestion of chicken manure and the biodegradation rate of ENR. The results showed that the addition of ENR increased the total biogas production, but at high concentrations, it reduced the production rate and delayed the peak period. ENR had different effects on archaea and bacteria, promoting hydrolysis reactions but inhibiting acetoclastic methanogens. The half-life period of ENR in the anaerobic digestion system was 9.16-10.83 days, with a biodegradation rate exceeding 80%.