In this method, crystallinity was determined by subtracting the amorphous contribution from diffraction spectra using an amorphous standard, i.e. lignin powder obtained from the solid product of hydrolysis after being dried and neutralized. Oak, pine, and EFB lignin were obtained from the hydrolysis of oak wood, pine wood, and EFB, respectively at 70 wt% decrystallization acid concentration, 30 C decrystallization reaction temperature and 78 C hydrolysis reaction temperature.