title: Hydrolysis and acidification of grass silage in leaching bed reactors.
abstract: Hydrolysis and acidification of grass silage (GS) was examined in leaching bed reactors (LBRs) under organic loading rates (OLRs) of 0.5, 0.8 and 1.0 kg volatile solids (VS)/m(3)/day. The LBRs were run in duplicate over five consecutive batch tests (Batch tests 1-5) to examine the effects of pH, leachate dilution and addition of inoculum on the process of hydrolysis and acidification. The highest GS hydrolysis yields of 52-58%, acidification yields of 57-60% and VS removals of 62-66% were obtained in Batch test 4. Increasing OLRs affected the hydrolysis yield negatively. In Batch test 4, the reduction of lignocellulosic materials was up to 74.4% of hemicellulose, 30.1% of cellulose and 9.3% of lignin within 32 days. Cellulase activity can be used as an indicator for the hydrolysis process. Methane production from the LBRs only accounted for 10.0-13.8% of the biological methane potential of GS.
authors.affiliation: Civil Engineering, College of Engineering and Informatics and Ryan Institute, National University of Ireland, Galway, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Xie
authors.forename: P G
authors.initials: PG
authors.lastname: Lawlor
authors.forename: J P
authors.initials: JP
authors.lastname: Frost
authors.forename: G
authors.initials: G
authors.lastname: Wu
authors.forename: X
authors.initials: X
authors.lastname: Zhan
mesh_terms: D000143:Acids / Q000737:chemistry*; D019149:Bioreactors / Q000382:microbiology*; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D008697:Methane / Q000302:isolation & purification / Q000378:metabolism*; D006109:Poaceae / Q000382:microbiology*; D012820:Silage / Q000382:microbiology*
chemical_list: D000143:Acids; C036909:lignocellulose; D008031:Lignin; D008697:Methane