PVA-gel　beads　were　used　as　a　biocarrier　in　a　lab-scale　UASB　reactor　treating　synthetic　wastewater　composed　of　corn　steep　liquor　(CSL)　with　the　aim　of　evaluating　its　use　as　a　growth　nucleus　to　enhance　granule　formation.　Over　117　days　of　operation,　the　organic　loading　rate　was　increased　to　22.5　kg　COD/m(3)/day　with　an　influent　COD　of　about　10.8　g/L　at　an　HRT　of　12　h　with　COD　removal　efficiencies　greater　than　87%.　By　the　end　of　the　study　period,　the　PVA-gel　turned　black　and　granule　formation　was　achieved　as　compared　with　the　Formation　Of　Much　fewer　natural　granules　without　the　PVA-gel　nucleus.　No　filamentous　bacteria　were　found　on　the　surface　or　interior　of　the　PVA-gel　beads.　The　PVA-gel　granules　had　an　average　settling　velocity　200　m/h　(5　cm/s),　and　a　biomass　attachment　of　0.93　g　VSS/g　PVA-gel.　The　required　time　for　formation　of　PVA-gel　granules　was　thus　demonstrated　to　be　shorter　than　that　of　ordinary　sludge　granules　under　the　experimental　conditions　used　in　this　study.　(c)　2008　Elsevier　Ltd.　All　rights　reserved.