Cannabis-based biofuels in a biorefinery approach

Abstract

Cannabis cultivation has been growing worldwide due to the legalization for either or both medicinal and recreational uses. Therefore, the amount of agriculture residues for this crop has the potential to become a promising feedstock for biofuels. This study aimed to demonstrate the complete valorization of cannabis biomass residues for biofuel production. Through the optimization of acid hydrolysis operation parameters (2:1 acid-to-biomass ratio, 60 min of swelling and 60 min of post-hydrolysis), it was possible to keep high glucose yields and low inhibitor formation. The use of CaCO3 to neutralize the cannabis hydrolysate allowed the fermentation with a final ethanol concentration of 30 gEtOH/100 gbiomass. After distillation, the vinasse was used to produce biogas (270 L CH4/kg VS). Therefore, a two-step acid hydrolysis can be considered as an efficient pretreatment for cannabis biomass to be used for the combined production of bioethanol and biogas.