# Bisulfite Pretreatment Improves Enzymatic Digestibility of Oil Palm Empty Fruit Bunch and Poplar Through Changing Its Structure and Lignin Distribution

## TL;DR

Bisulfite pretreatment makes plant materials like oil palm and poplar easier to break down by enzymes by altering their structure and lignin distribution.

## Contribution

The study reveals how bisulfite pretreatment changes the structure and lignin distribution to improve enzymatic digestibility in non-wood and wood materials.

## Key findings

- Bisulfite pretreatment creates pores in cell walls and removes lignin, loosening the tissue structure.
- The pretreatment improves cellulose accessibility and reduces lignin's negative impact on cellulase activity.
- The structural changes correlate with increased saccharification efficiency in pretreated EFB.

## Abstract

This paper investigated the changes in anatomy, ultrastructure and lignin distribution of oil palm empty fruit bunch (EFB) by bisulfite pretreatment. It was found that after bisulfite pretreatment, a large number of pores formed in the cell walls, and the removal of part of the lignin in the cell wall corner, partial middle layer, and other locations made the tissue structure of the EFB looser, which uncovered cellulose and broke the steric hindrance of cellulase access to cellulose in EFB, and also weakened the negative influence of lignin on cellulase. The changes can greatly contribute to the improvement of enzymatic hydrolysis after bisulfite pretreatment, which is consistent with the increased saccharification efficiency of the pretreated EFB. Poplar was also used to compare the differences and similarities between non-wood and wood materials.