Research paperMechanical pretreatment of biomass - Part I: Acoustic and hydrodynamic cavitation

•Acoustic and hydrodynamic cavitation were examined as mechanical pretreatments.•Acoustic cavitation of microcrystalline cellulose showed significant gains over no treatment.•Hydrodynamic cavitation increased the enzymatic digestibility of both raw and lime-treated sugarcane bagasse.•The energy cost of hydrodynamic cavitation is too expensive to be economical.

Acoustic and hydrodynamic cavitation were examined as suitable mechanical pretreatments for lignocellulosic biomass. Microcrystalline cellulose and lime-treated sugarcane bagasse were subjected to acoustic cavitation, whereas raw and lime-treated sugarcane bagasse were subjected to hydrodynamic cavitation. Acoustic cavitation successfully increased microcrystalline cellulose enzymatic digestibility by 37% compared to no acoustic cavitation treatment; however, there was no significant effect on lime-treated sugarcane bagasse. Hydrodynamic cavitation increased the enzymatic digestibility of both raw and lime-treated sugarcane bagasse. Best results were obtained using cavitation treatment of bagasse followed by lime treatment; the 3-d enzymatic digestion increased by 46% when compared to lime treatment only.