Sludge　alkaline　fermentation　has　been　reported　to　achieve　efficient　short-chain　fatty　acids　(SCFAs)　production.　Temperature　played　important　role　in　further　improved　SCFAs　production.　Long-term　SCFAs　production　from　sludge　alkaline　fermentation　was　compared　between　mesotherm　(30　+/-　2　degrees　C)　and　microtherm　(15　+/-　2　degrees　C).　The　study　of　90　days　showed　that　mesotherm　led　to　2.2-folds　production　of　SCFAs　as　microtherm　and　enhanced　the　production　of　acetic　acid　as　major　component　of　SCFAs.　Soluble　protein　and　carbohydrate　at　mesotherm　was　2.63-folds　as　that　at　microtherm　due　to　higher　activities　of　protease　and　a-glucosidase,　guaranteeing　efficient　substrates　to　produce　SCFAs.　Illumina　MiSeq　sequencing　revealed　that　microtherm　increased　the　abundance　of　Corynebacterium,　Alkaliflexus,　Pseudomonas　and　Guggenheimella,　capable　of　enhancing　hydrolysis.　Hydrolytic　bacteria,　i.e.　Alcaligenes,　Anaerolinea　and　Ottowia,　were　enriched　at　mesotherm.　Meanwhile,　acidogenic　bacteria　showed　higher　abundance　at　mesotherm　than　microtherm.　Therefore,　enrichment　of　functional　bacteria　and　higher　microbial　activities　resulted　in　the　improved　SCFAs　at　mesotherm.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.