*2.5. Statistical Analysis*

All experiments and analyses were carried out in duplicate. All intervals and error bars reported represent two times the standard deviation. The data acquired were statistically analyzed using MINITAB®® 17 (Minitab Ltd., Coventry, UK). A general linear model with a confidence interval of 95% was applied for the analysis of variance (ANOVA); statistical differences were identified at *p*-value <0.05. To have a better understanding of the extent of differences between results obtained, pairwise comparisons according to the Bonferroni test were performed.

## **3. Results**

Oil palm empty fruit bunch was pretreated using acid-catalyzed ethanol organosolv to achieve deconstruction into three high-quality streams, namely, glucan-rich, lignin-rich, and hemicellulosic compounds-rich fractions. The effect of pretreatment factors, namely, acid catalyst type and concentration, temperature, retention time, and S/L ratio on lignin purity and recovery were studied. A mixture of evaporated glucan and hemicellulosic compounds-rich fractions obtained at the best condition of pretreatment was then enzymatically hydrolyzed in order to investigate the effect of organosolv pretreatment on glucan digestibility. The untreated OPEFB was also enzymatically hydrolyzed as a control.
