[58] The combined severity (CS) evaluates the severity of a treatment using time, pH and temperature. Highest xylose yields are obtained for low severity (CS<2-3) while higher values increase saccharides degradation into furanic compounds (furfural for pentose and 5-HMF for hexose), confirming the use of DAE for optimal saccharification. Even higher CS will dehydrate carbohydrates further to form pseudo-lignin increasing the amount of Klason's