Monitoring ARGs and microbial communities in different stages of biogas plants

Animal husbandry is a crucial sector using antibiotics. Livestock manure is a common substrate for large-scale anerobic digestion (AD) systems. Depending on the medical treatment of the animals the manure is often contaminated with antibiotics and antibiotic resistant genes (ARGs). It was pointed out that AD systems can be potential reservoirs for multi-resistant bacteria considering the continuous load of antibiotics and various resistant bacteria from livestock manure. However, the survival of resistant bacteria from livestock is assumed to be reduced in a well-managed AD process. It is expected that high temperature has a positive effect of both degradation and ARG removal.Samples were collected from six biogas plants in Germany or Denmark. Six ARGs (sul1, sul2, tetA, tetM, tetX and qnrD) were selected and quantified to see how abundant they are in different stages of biogas plants. ARGs are generally reduced through biogas plants. Bacterial community and methanogenic archaea community were also analyzed.