Ecological succession reveals microbial driving factors for partially and completely ammonia-inhibited biogas processes

In the biogas process, the feeding with ammonia-rich substrate implies in the potential inhibition of the microbial communities. In this study we investigated the gradual substrate change in two parallel reactors, which were fed initially with only maize silage in mono-digestion and later also with chicken manure in co-digestion. Other two reactors operated at the same time and under same conditions in mono-digestion were used as controls. All four laboratory-scale continuous stirred tank reactors were under mesophilic conditions. For better understanding the microbial succession in the reactors that suffered ammonia inhibition, we have performed pyrosequencing analyses in the samples collected from two different sampling points: during mono- and co-digestion under ammonia inhibition.