16S metabarcoding of Anaerobic digesters microbiome exposed to ammonium. Anaerobic digesters microbiome exposed to ammonium

Anaerobic digestion (AD) is an attractive biotechnological process for wastewater bioremediation and bioenergy production in the form of methane-rich biogas. However, AD can be inhibited by ammonium generated by protein-rich effluent, commonly found in agroindustrial activities. Insights in the microbial community composition and identification of AD keyplayers are crucial for anticipating process impairments in response to ammonium stress. They can also help in defining an optimal microbiome adapted to high ammonium levels. Here, we compared two strategies for acclimation of AD microbiome to increasing ammonium concentration, to better understand the impact of this stress on the methanogens and their bacterial partners. Our results suggest that long term cumulative exposure to ammonia disrupted more strongly the AD microbiome than direct (independent) ammonium additions. We identified bioindicators with different NH4+ tolerance capacity among VFA producers and syntrophic VFA oxidizers.