Assessment of hydrothermal pretreatment of various lignocellulosic biomass with CO 2 catalyst for enhanced methane and hydrogen production

Cigdem Eskicioglu (1, 2) , Florian Monlau (3) , Abdellatif Barakat (3, 4) , Ivet Ferrer (5) , Prasad Kaparaju (1, 6) , Eric Trably (1) , Hélène Carrère (1)

1 LBE - Laboratoire de Biotechnologie de l'Environnement [Narbonne]
2 UBC Bioreactor Technology Group, School of Engineering
3 UMR IATE - Ingénierie des Agro-polymères et Technologies Émergentes
4 Materials Science and Nano-engineering Department
5 GEMMA – Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering
6 Griffith School of Engineering, Nathan Campus, Griffith University

Hydrothermal pretreatment of five lignocellulosic substrates (i.e. wheat straw, rice straw, biomass sorghum, corn stover and Douglas fir bark) were conducted in the presence of CO2 as a catalyst. To maximize disintegration and conversion into bioenergy (methane and hydrogen), pretreatment temperatures and subsequent pressures varied with a range of 26–175 °C, and 25–102 bars, respectively. Among lignin, cellulose and hemicelluloses, hydrothermal pretreatment caused the highest reduction (23–42%) in hemicelluloses while delignification was limited to only 0–12%. These reductions in structural integrity resulted in 20–30% faster hydrolysis rates during anaerobic digestion for the pretreated substrates of straws, sorghum, and corn stover while Douglas fir bark yielded 172% faster hydrolysis/digestion due to its highly refractory nature in the control. Furans and phenolic compounds formed in the pretreated hydrolyzates were below the inhibitory levels for methane and hydrogen production which had a range of 98–340 ml CH4/g volatile solids (VS) and 5–26 ml H2/g VS, respectively. Results indicated that hydrothermal pretreatment is able to accelerate the rate of biodegradation without generating high levels of inhibitory compounds while showing no discernible effect on ultimate biodegradation.

Mots clés: Anaerobic digestion; Dark fermentation; Straw; Sorghum; Corn stover; Douglas fir bark; pretreatment; bioenergy

Mots clés: prétraitement; bioénergie; traitement hydrothermique; dégradation de la lignocellulose; digestion anaérobie; biodégradation

Domaines: Ingénierie des aliments

Cigdem Eskicioglu, Florian Monlau, Abdellatif Barakat, Ivet Ferrer, Prasad Kaparaju, et al.. Assessment of hydrothermal pretreatment of various lignocellulosic biomass with CO 2 catalyst for enhanced methane and hydrogen production. Water Research, 2017, 120, pp.32-42. ⟨10.1016/j.watres.2017.04.068⟩. ⟨hal-01604979⟩