Novel dual-action vanillic acid pretreatment for efficient hemicellulose separation with simultaneous inhibition of lignin condensation

Aromatic acids play a selective role in the separation of hemicellulose. Phenolic acids have demonstrated an inhibitory effect on lignin condensation. In the current study, vanillic acid (VA), which combines the characteristics of aromatic and phenolic acids, is used to separate eucalyptus. The efficient and selective separation of hemicellulose is achieved simultaneously at 170 degrees C, 8.0% VA concentration, and 80 min. The separation yield of xylose increased from 78.80% to 88.59% compared to acetic acid (AA) pretreatment. The separation yield of lignin decreased from 19.32% to 11.19%. In particular, the & beta;-O-4 content of lignin increased by 5.78% after pretreatment. The results indicate that VA, as a carbon positive ion scavenger, it preferentially reacts with the carbon-positive ion intermediate of lignin. Surprisingly, the inhibition of lignin condensation is achieved. This study provides a new starting point for the development of an efficient and sustainable commercial technology by organic acid pretreatment.

Automated summary

Aromatic acids are used selectively in the separation of hemicellulose, while phenolic acids inhibit lignin condensation. The current study utilizes vanillic acid (VA), which combines the characteristics of aromatic and phenolic acids, for the separation of eucalyptus. Under specific conditions (170°C, 8.0% VA concentration, and 80 min), efficient and selective separation of hemicellulose is achieved. Compared to acetic acid pretreatment, the yield of xylose increased from 78.80% to 88.59% and the yield of lignin decreased from 19.32% to 11.19%. In addition, there was an increase in the β-O-4 content of lignin by 5.78% after pretreatment. This study provides a new starting point for the development of efficient and sustainable commercial technology through organic acid pretreatment.