*2.3. Enzymatic Hydrolysis*

The glucan-rich and hemicellulosic compounds-rich fractions obtained at the best conditions found in the study were mixed and evaporated using a rotary evaporator (LABO ROTA 20, Heidolph, Schwabach, Germany) at 110 ◦C, 40 rpm, and at a vacuum pressure of 100 mPa. The concentrated slurry had a glucan loading of 1.37% (w/v) and 1.85% (w/v) of total solid. Cellic®® Ctec3 enzyme solution was prepared by 10× dilution with ultra-pure water followed by sterile filtration using disposable disc filters with a pore size of 0.2 µm (GVS, Findlay, OH, USA). Diluted enzyme solution was added to the slurry based on the enzyme activity and glucan content (10, 15, 20, and 30 FPU/g glucan). Enzymatic hydrolysis was performed in 20 mL Erlenmeyer flasks, containing 10 mL of slurry adjusted to pH 5.2, that were incubated in a water-bath at 50 ◦C and shaking at 125 rpm for 24 h. Samples of 1.5 mL were withdrawn at 18 h and 24 h for chromatographic analysis. The percentage of glucan hydrolysis was then calculated based on the ratio between the amount of glucose released after hydrolysis and the theoretical maximum. Untreated OPEFB and evaporated hemicellulosic compounds-rich fraction were also used for enzymatic hydrolysis for comparison purposes.
