Answer:
physical processes
chemical methods
physicochemical processes
biological methods
and several combinations thereof to fractionate the lignocellulose into its components.
Step-by-step explanation:
Pretreatment involves the use of physical processes (e.g., size reduction, steaming/boiling, ultrasonication, and popping), chemical methods (e.g., acids, bases, salts, and solvents), physicochemical processes (e.g., liquid hot water and ammonium fibre explosion or AFEX), biological methods (e.g., white-rot/brown-rot fungi and bacteria), and several combinations thereof to fractionate the lignocellulose into its components.