Semi-continuous subcritical hydrolysis of orange waste biomasses for integrated production of fermentable sugars and platform chemicals

Abstract

Results for the obtaining of fermentable sugars (FSs) and platform chemicals (PCs) from the subcritical hydrolysis of orange wastes (peel and bagasse) are presented. Unlike what is typically reported in similar studies involving lignocellulosic biomasses, the hydrolysis process was performed in a semi-continuous configuration, which allowed the examination of how temperature (180 to 220 °C) and pressure (15 to 25 MPa) influenced the compounds’ kinetic profile. Furthermore, studies have been found that evaluated these points for such biomasses. The best yields of hydrolyzed solution were obtained for biomasses pretreated by soxhlet with hydrolysis conducted at 180 °C and 15 MPa (orange peel, OP) and 200 °C and 20 MPa (orange bagasse, OB), yielding 5.31 and 4.26 g (100 g biomass)−1, respectively. Among the FSs, xylose was the monosaccharide predominantly obtained for both biomasses: 21.12 g L−1 for OP pretreated with SCO2 (hydrolysis at 180 °C and 15 MPa); and 24.45 g L−1 for untreated OB (hydrolysis at 220 °C and 25 MPa). Regarding the PCs, furfural was the main compound obtained for both biomasses: 10.86 g L−1 for untreated OP and 7.33 g L−1 for OB pretreated with SCO2, with both hydrolysis conducted at 220 °C and 25 MPa.