Mesophilic and thermophilic anaerobic fermentation performance of waste activated sludge ( WAS) pretreated by enzymes catalysis associated with microbial community shifts were investigated. WAS disintegration was boosted considerably by enzymolysis with 8750 mg/L of soluble COD release within 180 min. Mesophilic anaerobic fermentation ( MAF ) produced nearly equal VFA accumulation with over 3200 mg COD/L compared with that of thermophilic fermentation ( TAF ) . Bacterial community consortia showed great shifting differences in dynamics of main T-RFs between MAF and TAF. Moreover, MAF was conducive to form intermediate bacterial community evenness compared to TAF, which preserved a robust function of VFA production. The enzymes catalysis prompted bio-energy ( electricity) recovery potential of WAS organics via anaerobic fermentation ( MAF/TAF ) with evaluating electricity conversion efficiency of 0.75-0.82 kW·h/kg VSS (3.9 times higher than control test). Finally, this study proposed some novel thinking on future WAS treatment/management towards energy recovery coupled with energy-sufficient wastewater treatment by co-locating WAS anaerobic fermentation, MFC plant with wastewater treatment plant(s).