LAUSR

Abstract Price hikes in conventional fuels coupled with sustainability concerns result into growing attraction towards lignocellulosic biomass conversion to biofuels. The hydrothermal pretreatment (HP) impact on structural characteristics of biomass and released inhibitory compounds linked to anaerobic digestion represent a knowledge gap and requires a critical review. In this review, HP chemistry, different hydrothermal processing techniques, inhibitory compounds production mechanism in the hydrolysate, and the impact of pretreatment parameters on biological conversion efficiency in products of biotechnological interest are discussed. Countercurrent flow-through hydrothermal reactor was found a better choice for high carbohydrate concentration in the hydrolysate. Anaerobic digestion is discussed in response to HP and morphological changes in biomass associated with lignin dissolution. Finally, literature previously published for techno-economic and environmental analysis pertinent to HP linked to anaerobic digestion process has been summarized and concluded that it requires much research for the decision makers.