Microbial and archaeal population with simple substrate at different salts concentrations

Volatile fatty acid accumulation is a common issue encountered in anaerobic digestion, indicating potential process failure through the inhibition of microorganisms consuming those acids. However, the related inhibition mechanisms and thresholds remain poorly characterized for digesters treating concentrated feedstocks such as food waste. In this study, the inhibition of acetate or propionate consumers was assessed when exposed to various salts (NH4HCO3, NaHCO3 or KHCO3) under mesophilic condition. Specific methanogenic activity was monitored and 16S rRNA gene Illumina sequencing was performed to determine the structure of the archaeal and microbial community depending on operational conditions (substrate and cation concentration).