Klason lignin and sugar content determination. Klason lignin and sugar determination was performed following a reported procedure. For the compositional analysis of white birch, the sample was first dried at 105°C overnight followed by cooling to room temperature under static vacuum in a desiccator containing CuSO4 as drying agent. The dried solid was extracted three times with an ethanol:water mixture (4:1 v/v and 20 mL g -1 ) followed by water (20 mL g -1 ) by sonication for 30 minutes. The sample was then dried at 105°C overnight followed by cooling to room temperature under static vacuum in a desiccator containing CuSO4 as a drying agent.