Effects Of Oxytetracycline On Archaea Community And ARGs During Anaerobic Digestion Process

Antibiotics are being used as veterinary medicines for therapeutic and sub therapeutic treatments and as feed additives to promote the growth of animals. Many of these compounds exhibit poor retention within the animal gut and intestine during the digestion, resulting in the excretion of potent parent and daughter products. If we take manure contain residual antibiotics as materials for anaerobic digestion, this situation may cause negative effect on the process. Tetracycline antibiotics(TC, CTC, OTC) are the most commonly used antibiotics in China. There already have many literatures about TC and CTC, but less about OTC. This study intend to research the effects of spiked OTC on methane production, enzyme activities, OTC content, microbial community and Tetracycline ARGs in lab scale unit. The results are as following paragraphs.1. The effect of OTC on methane cumulative production, enzyme activities and OTC contentOTC could promote methane cumulative production and urease activities in the first 10 days, then turned to an obstacle both for methane cumulative production and urease activities. OTC inhibited the dehydrogenase activity till the 30 th day, L and M treatments showed no significant difference with CK treatment. The degradation of OTC mainly happened in the first 30 days.2. The effect of OTC on archaea communitiesDGGE profile indicated that OTC had little negative impact on archaea communities. The archaea community was found dominated by Methanocorpusculum labreanum Zand Methanosaeta concilii GP-6, the consequence also told that mesophilic anaerobic digestion was able to wipe off the Acinetobacter sp proved to be one kind of pathogens. The SEM results demonstrated the population of microbial increased at prior period, then decreased. The anaerobic digestion system mainly consisted of Brevibacterium, Sphaerophorus and Actinomycetaceae.3. The effect of OTC on Tetracycline ARGsFour kinds of ARGs had been detected, they were tet(M),tet(Q),tet(W)and tet(C). L and M treatments eliminated ARGs more effectively than CK, except tet(W). H treatment showed worst performing in wiping off ARGs. The change of ARGs abundance may related with the fluctuation of ARGs host microbial population. The AD treatments was not good at eliminating tetracycline ARGs, therefore more treatments were needed to reduce the risk to environment.