The response regularity of biohydrogen production by anthracite H₂-producing bacteria consortium to six conventional veterinary antibiotics

The impact of antibiotics on H₂-producing bacteria must be considered in the industrialization of biological H₂ production using livestock manure as raw resources. However, whether antibiotics that may be contained in excreta will threaten the safety of biohydrogen production needs to be researched. This study explored the impact characteristics and mechanism of six single antibiotics and three groups of compound antibiotics on H₂ production. Experiments confirmed that most antibiotics have different degrees of H₂ production inhibition, while some antibiotics, which like Penicillin G, Streptomycin Sulfate, and their compound antibiotics, could promote the growth of Ethanoligenens sp. and improve H₂ yield on the contrary. Comprehensive analysis shows that the main inhibitory mechanisms were: (1) board-spectrum inhibition, (2) partial inhibition, (3) H₂ consumption enhancement; and the enhancement mechanisms were: (1) enhance the growth of H₂-producing bacteria, (2) enhanced starch hydrolysis, (3) inhibitory H₂ consumption or release of acid inhibition. Meanwhile, experiment found that the effect of antibiotics on H₂ producing was not only related to type, but also to dosage. Even one kind of antibiotic may have completely opposite effects on H₂-producing bacteria under different dosage conditions. Inhibition of H₂ yield was highest with Levofloxacin at 6.15 mg/L, gas production was reduced by 88.77%; and enhancement of H₂ yield was highest with Penicillin G at 7.20 mg/L, the gas production increased by 72.90%. In the selection of raw material, the type and content of antibiotics demand a detailed investigation and analysis to ensure that the sustainability of H₂ yield.