A Review of Lignocellulose Change During Hydrothermal Pretreatment for Bioenergy Production

Lignocellulosic biomass, as a sustainable bioenergy source, can be used to supplement fossil fuel. However, the utilization of lignocellulosic biomass for energy production has not been widely applied because of the complicated and stable structure of plant cell wall. Hydrothermal pretreatment of lignocellulosic biomass is an efficient method to disrupt lignin and hemicellulose and expose cellulose. Nowadays, many literatures demonstrated the mechanisms of hydrothermal pretreatment and the change of lignocellulosic biomass (including cellulose, hemicellulose and lignin) during hydrothermal pretreatment. Up to now, however, there is no review on this field. This paper reviews the research effort on hydrothermal pretreatment of lignocellulosic biomass and explains how the hydrothermal pretreatment affects the properties of lignocellulosic biomass. This review puts emphasis on the detailed changes of cellulose, hemicellulose and lignin during hydrothermal pretreatment. In addition, the future research directions are also prospected.