Cooking with active oxygen and solid alkali facilitates lignin degradation in bamboo pretreatment

Cooking with active oxygen and solid alkali (CAOSA), developed by our group, is a promising alternative to both clean pulping and biomass pretreatment since it is a facile technique with advantages of environmental benignity and easy alkali recovery. Through comparative analysis using 2D-HSQC NMR, the superior delignification efficiency of the CAOSA process could be attributed to the more efficient cleavage of the benzene ring in lignin, which is in sharp contrast to the conventional pulping route. Abundant organic acids were detected in the product solution, which is also known as yellow liquor (YL). In addition, acid insoluble degradation products (AIDPs) containing aromatic compounds were present in the YL, which were separated and collected. The low AIDP content in the YL suggested the highly efficient decomposition of the aromatic rings. This delignification study not only presents a deeper investigation of the CAOSA process itself but also provides guidance for further research on biomass-lignin degradation.