Effect of ammonia exposure and acclimation on the performance and the microbiome of anaerobic digestion

Francesc Puig-Castellví^a,b, Laëtitia Cardona^b, Chrystelle Bureau^b, Delphine Jouan-Rimbaud Bouveresse^c,d, Christophe B.Y.Cordella^c,d, Laurent Mazéas^b, Douglas N.Rutledge^a,e, Olivier Chapleur^b

Université Paris-Saclay, INRAE, AgroParisTech, UMR SayFood, 75005 Paris, France.

Abstract

In this study, the effect of ammonia (NH₃) as a disturbance on the microbial communities during anaerobic digestion (AD) was examined. NH₃ was progressively added into 5 stabilized semi-continuous bio-reactors containing biowaste at 5 different NH₃ loading rates until an inhibitory concentration was reached, and maintained at this concentration for 3 hydraulic retention times (75?days). The performance and the microbial community of the digesters were analyzed. The digesters performances were hindered at higher NH3 loading rates, marked by lower biogas productions and the accumulation of volatile fatty acids. At the microbial community level, changes depended on the NH₃ loading rate. For instance, the digester with the highest NH₃ loading rate showed a hydrogenotrophic methanogenic profile resulting from the growth of Methanosarcina spp. and acetate-consuming microorganisms, as well as the restricted growth of obligate acetoclastic archaea. This work can be helpful for the design of future acclimation strategies in AD.

Graphical abstract

Keywords: 16S rDNA sequencing, Anaerobic digester, Ammonia.