A green process for producing xylooligosaccharides via autohydrolysis of plasma-treated sugarcane bagasse

Abstract

Due to alarming energy consumption and population growth, the transition to a circular economy is being pursued by searching for alternative resources to produce chemicals and energy. In this regard, lignocellulosic biomass, as the most abundantly accessible plant material, is a suitable alternative for satisfying this high demand. Sustainable lignocellulose biorefineries could convert cellulose, hemicellulose, and lignin into high-value products. Most available approaches prioritize cellulose and lignin over hemicellulose. In this work, autohydrolysis treatment of sugarcane bagasse is developed to produce xylooligosaccharides (XOS) with a variable degree of polymerization (2−6) using low-temperature atmospheric-pressure plasma and ball-mill treatment on raw bagasse. The reactive oxygen, ozone, hydronium ions (H3O+), and nitrogen species generated by plasma increase hemicellulose conversion. XOS hydrolysate obtained from plasma pre-treated samples (41.1%) was quantified for xylobiose (12.1%), xylotriose (10.1%), xylotetrose (6.9%), xylopentaose (7.1%), and xylohexaose (4.9%) (6 h of autohydrolysis at 135 °C). Xylan hydrolysate was also yielded 21.2% xylose, and 2.2% furfural, respectively. The entire process (plasma and autohydrolysis) was conducted in water without using any other chemicals. These results suggest the potential role of plasma pre-treatment prior to hydrothermal treatments to selectively produce XOS.