Xylooligosaccharides, monosaccharides, and pH-sensitive carbon dots production from Toona sinensis branches using organic acid hydrolysis and hydrothermal treatment

The present study focused on exploring the effectiveness of delignification of the lignocellulosic biomass and pHcontrolled organic acid hydrolysis in the cascade utilization of Toona sinensis branches (TB) for the production of xylooligosaccharides (XOS), monosaccharides and carbon dots (CDs). The hydrolysis of delignified TB with propionic acid (PA) resulted in a high XOS yield of 48.1 % at pH 3.0, 170 degrees C for 60 min. The PA hydrolyzates upon hydrolysis with xylanase yielded 61.2 % XOS. The solid residue from XOS production was subjected to cellulase hydrolysis, resulting in a glucose yield of 87.8 %. Furthermore, CDs were synthesized through a green hydrothermal method using the solid residue from cellulase hydrolysis as a precursor. These CDs exhibited excitation-independent and pH-dependent fluorescence properties. This study demonstrated the integrated utilization of TB for efficient production of XOS, monosaccharides, and pH-sensitive CDs.