Aqueous Ammonia Soaking of Wheat Straw at ambient temperature for Enhancing the Methane Yield: Process Optimization by Response Surface Methodology

Anna Lymperatou, Hariklia N. Gavala, Ioannis V. Skiadas*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


Aqueous Ammonia Soaking (AAS) at ambient temperature was applied to wheat straw under different conditions in order to maximize the CH4 yield through mesophilic anaerobic digestion. The effects of the NH3 concentration, duration of AAS and solid-to-liquid ratio were studied on the resulting CH4 yield and the solubilization degree of the pretreated wheat straw. A strong interaction among the NH3 concentration and the duration of AAS was observed. The optimal conditions found were 18% w/w NH3, 7 days of duration and 50 g straw/ L reagent, leading to a 43% increase of the CH4 yield in 17 days of digestion. Compositional analysis of the optimally-treated wheat straw revealed that a significant solubilization of hemicellulose took place during AAS together with a moderate lignin removal (9%).
Original languageEnglish
JournalWaste and Biomass Valorization
Publication statusAccepted/In press - 2020


  • Wheat straw
  • Pretreatment
  • Snaerobic digestion
  • Optimization
  • Aqueous ammonia soaking
  • Methane

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