Advancements in Giant Reed (Arundo donax L.) Biomass Pre-Treatments for Biogas Production: A Review

Giant reed is a non-food, tall, rhizomatous, spontaneous perennial grass that is widely diffused in warm-temperate environments under different pedo-climatic conditions. In such environments, it is considered one of the most promising energy crops in terms of economic and environmental sustainability, as it can also be cultivated on marginal lands. Owing to its complex and recalcitrant structure due to the lignin content, the use of giant reed as a feedstock for biogas production is limited. Thus, pre-treatment is necessary to improve the methane yield. The objective of this review was to critically present the possible pre-treatment methods to allow the giant reed to be transformed in biogas. Among the studied pre-treatments (i.e., hydrothermal, chemical, and biological), alkaline pre-treatments demonstrated better effectiveness in improving the methane yield. A further opportunity is represented by hybrid pre-treatments (i.e., chemical and enzymatic) to make giant reed biomass suitable for bio-hydrogen production. So far, the studies have been carried out at a laboratory scale; a future challenge to research is to scale up the pre-treatment process to a pilot scale.

Automated summary

Giant reed, a non-food perennial grass, has great potential for biogas production in warm-temperate environments. However, its complex structure limits its use as a feedstock. This review critically evaluates various pre-treatment methods and suggests alkaline pre-treatment as the most effective in improving methane yield. Hybrid pre-treatments, combining chemical and enzymatic methods, also show promise for bio-hydrogen production. Scaling up the pre-treatment process to a pilot scale is recommended for further research.