Fate of pathogenic bacteria in five full-scale biogas plants monitored using cultivation, dPCR, and shotgun metagenomics: Insights from each approach

wet weight, compatible with regulatory thresholds. Comparing the three methods revealed that shotgun metagenomics detected a greater diversity of pathogenic species in biowaste, including S. aureus and C. botulinum. Acidophilic conditions in hydrolysis tank effectively hygienized the biowaste. In contrast, the four agricultural biogas plants showed limited effect on the three indicator bacteria, as indicated by dPCR. This study demonstrates, for the first time, the added value of combining dPCR and shotgun metagenomics to assess pathogen dynamics in biogas plants. Together, these methods provide a more comprehensive and specific view of microbial contaminants, as illustrated by the detection of Enterococcus cecorum in digestates.