Identification and quantification of key microbial trophic groups of methanogenic glucose degradation in an anaerobic digester sludge

► Key trophic groups in anaerobic glucose degradation were identified and quantified. ► Population size of propionate degraders was the smallest among the trophic groups. ► Population size of acetate degraders was comparable to the glucose degraders. ► The specific degradation rate of acetate was low (1/28 of that of glucose). ► We explained why the degradation of propionate and acetate was rate-limiting.