Improving anaerobic digestion with support media: Mitigation of ammonia inhibition and effect on microbial communities

This study aimed at providing a better understanding of the influence of support media (10 g/L of zeolites, 10 g/L of activated carbons, and 1 g/L of chitosan) on key phylotypes steering anaerobic digestion (AD) performance in presence of 19 g/L of Total Ammonia Nitrogen (TAN) within batch digesters. Support media did not influence TAN concentration. However, both zeolites and activated carbon 1 reduced methanization lag phase by 47% and 25%, respectively. By contrast, activated carbon 2 and chitosan led to an increase of methanization lag phase by 51% and 32%, respectively. 16S rRNA gene sequencing revealed that zeolites preserved Methanosarcina and enhanced Methanobacterium. In presence of activated carbon 1, Methanoculleus, became predominant earlier than without support while chitosan and activated carbon 2 limited its implantation. This study highlighted potentialities to use supports to enhance AD stability under extreme TAN concentration and evidenced their specific influence on the microbiota composition.