Lignocellulosic materials contributing the large proportion to the biomass resource are mainly composed of carbohydrate polymers (cellulose, hemicellulose), and aromatic macromolecules (lignin). Pre-fractionating lignocellulose is considered as the foundational step to establish an economical and sustainable lignocellulosic biorefinery. Firstly, the distinction between lignocellulose fractionation technologies and pretreatment methods for cellulosic ethanol production is discussed. Afterwards, five prior-fractionating strategies of lignocellulose for the biorefinery process are elaborated, including cellulose-first processing, lignin-first processing, hemicellulose-first processing, lignin & hemicellulose-first processing, and cellulose & hemicellulose-first processing. And then industrial applications of hemicellulose-first processing in our country are reviewed. Ultimately, the future perspective on lignocellulose fractionation technologies are given. The aim of this review is to provide new insights into the lignocellulosic biorefinery based on the fractionating of lignocellulose.
Contents
1 Introduction
2 The similarity and difference between lignocellulose pretreatment and fractionation
3 Prior-fractionating strategies of lignocellulose for biorefinery
3.1 Cellulose-first processing
3.2 Lignin-first processing
3.3 Hemicellulose-first processing
3.4 Lignin&hemicellulose-first processing
3.5 Cellulose&hemicellulose-first processing
4 Industrial cases of hemicellulose-first strategy
4.1 Co-production of dissolving pulp and xylitol/furfural
4.2 Co-production of citric acid and xylitol/arabinose
4.3 Co-production of xylooligosaccharide and lignocellulosic ethanol
4.4 Co-production of furfural and ethanol
4.5 Co-production of vehicle fuels and chemicals
5 Conclusion