Hydrolysis and acidification of grass silage in leaching bed reactors

Authors

Sihuang Xie, National University of IrelandFollow
Peadar G. Lawlor, Animal and Grassland Research and Innovation Centre
J P. Frost, Agri-Food And Biosciences Institute
Guangxue Wu, Tsinghua University
Xinmin Zhan, National University of Ireland

RIS ID

111085

Publication Details

Xie, S., Lawlor, P. G., Frost, J. P., Wu, G. & Zhan, X. (2012). Hydrolysis and acidification of grass silage in leaching bed reactors. Bioresource Technology, 114 406-413.

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)/m³/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.