This　study　aimed　at　exploring　a　new　approach　for　producing　volatile　fatty　acids　(VFAs)　from　excess　sludge　(ES).　Two　representative　alkali-tolerant　bacteria　(HIT-01　and　HIT-02)　were　isolated　from　ES,　and　inoculated　separately　or　jointly　into　ES　to　investigate　their　effects　on　VFAs　accumulation,　soluble　organic　compounds　concentrations,　and　bacterial　community　structure　of　ES　under　alkaline　anaerobic　conditions　(pH　10.0).　Four　fermentation　conditions　were　examined　for　20　days.　Joint-inoculation　with　the　two　strains　achieved　the　highest　VFAs　concentration　(3139　mg/L).　Acetic　and　propionic　acids　were　the　dominant　acid　species.　On　the　9th　day,　all　the　inoculated　ES　had　the　higher　concentrations　of　soluble　organic　compounds　than　the　un-inoculated　control　ES.　Denaturing　gradient　gel　electrophoresis　(DGGE)　analysis　revealed　that　these　two　strains　(HIT-01　and　HIT-02)　became　predominant　in　the　bacterial　community　during　alkaline　anaerobic　fermentation.　The　results　demonstrated　that　bioaugmentation　might　be　useful　for　enhancing　VFAs　accumulation　from　ES.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.