A quality-assured workflow for microbial profiling in anaerobic digesters using integrated nucleic acid purification and verification

This study establishes a unified workflow for quantitative and taxonomic characterization of microbial populations and transcriptional activity in anaerobic digestion reactors under varying process conditions. Absolute abundances and transcription levels of methanogenic mcrA/mrtA genes and bacterial 16S rRNA/-rDNA targets were determined via (RT)qPCR, complemented by Illumina MiSeq amplicon sequencing and ASV-based bioinformatic processing with comprehensive chimera curation and taxonomic assignment. Ecophysiological performance was evaluated using the Metabolic Quotient and transcript-to-gene ratios as functional indices for process-state diagnosis.