Effect of the operating conditions on the anaerobic digestion of wheatgrass for chemicals and energy production

Igor M. O. Silva, Davide Dionisi* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
7 Downloads (Pure)


The aim of this study was to investigate anaerobic digestion of wheatgrass in the absence of hydrolytic pre-treatments. The effect of solids retention time (SRT) (1-64 d), inoculum acclimation (0-80 d acclimation), temperature (40-70 °C) and buffer capacity (20-200 mM phosphate buffer) on conversion of the feedstock, yield and composition of liquid-phase products (ethanol and short-chain organic acids, SCOAs) and COD removal was investigated in semi-continuous (intermittent feed) completely mixed reactors.

SRT had the most important effect on process performance. Biodegradation of the feedstock was favoured at high SRT, with 61 % removal of volatile suspended solids and 84 % removal of total carbohydrates at SRT 64 d. However, low yield of liquid-phase products was observed at high SRT because of strong methanogenic activity (57 % removal of the total COD). The highest yield of liquid-phase products was 20 % (COD basis) at SRT 8 d. Although high biodegradation of the feedstock was observed after long-term batch acclimation (30 and 80 d), once the digestion conditions were switched to semi-continuous at short SRT (2 d) the biodegradation of the feedstock decreased considerably. The best process performance was observed at 40 OC.
Original languageEnglish
Pages (from-to)233-244
Number of pages12
JournalBiomass Conversion and Biorefinery
Issue number2
Early online date8 Jun 2020
Publication statusPublished - Feb 2022

Bibliographical note

Open Access via the Springer Compact Agreement


The authors wish to acknowledge Carnegie Trust for the Universities of Scotland (Research Incentive Grant 70307), CAPES (Coordination for the Improvement of Higher Education Personnel) for the financial support (Process 011944/2013-07), Mrs Elizabeth Hendrie and Ms Gabriela Paupitz for the technical collaboration and Mr Andrew Rennie (Gask Farm, Turriff, Aberdeenshire, UK) for kindly providing the inoculum used in the experiments.


  • anaerobic digestion
  • carboxylates
  • lignocellulose
  • grass
  • biorefinery


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