Unlocking full potential of bamboo waster: Efficient co-production of xylooligosaccharides, lignin, and glucose through low-dosage mandelic acid hydrolysis with alkaline processing.

Mandelic acid (MA), a natural and environmentally friendly organic acid, demonstrates high selectivity and efficiency in hydrolyzing hemicellulose, making it an excellent candidate for xylooligosaccharides (XOS) production at low acid dosages. Despite its potential, the application of MA for XOS production has not been evaluated. The study first investigated the effectiveness of MA in hydrolyzing hemicellulose in bamboo into XOS. Under optimized conditions (50 mM MA, 180 °C, 45 min), a high XOS yield of 65.9 % was achieved, with a total xylobiose and xylotriose yield of 43.5 %. Subsequent alkaline pretreatment enabled 92.1 % lignin removal from MA-pretreated bamboo. The recovered lignin exhibited a high purity of 95.2 % and retained fundamental structure and functional groups of native lignin. The resulting residue displayed enhanced crystallinity and accessibility, with reduced hydrophobicity and surface area lignin compared to untreated bamboo. At high substrate concentration of 20 %, cellulase hydrolysis resulted in a glucose conversion efficiency of 83.9 %. Overall, this integrated strategy offered an efficient approach for the co-production of valuable XOS, lignin, and glucose from bamboo. The efficient energy utilization and economic viability further highlighted the potential of this method for large-scale industrial applications, making it an attractive option for biomass valorization.