Detection of active butyrate-degrading microorganisms in methanogenic sludges by RNA-based stable isotope probing

Butyrate-degrading bacteria in four methanogenic sludges were studied by RNA-based stable isotope probing. Bacterial populations in the C-13-labeled rRNA fractions were distinct from unlabeled fractions, and Syntrophaceae species, Tepidanaerobacter sp., and Clostridium spp. dominated. These results suggest that diverse microbes were active in butyrate degradation under methanogenic conditions.