Sustainable valorization of coffee pulp: Evaluation of pretreatment on phenolic compounds extraction and subsequent anaerobic digestion of the residual biomass

Coffee pulp is the main solid waste derived from wet processing, while its valorization can benefit both the environment and the regional economy. This study examines the holistic approach of phenolic compounds extraction, coupled with the further valorization of the residual biomass through anaerobic digestion, while an economic assessment indicates the most favored pathway. Several pretreatment methods were considered (squeezing, grinding, ultrasounds (US), microwaves, and supercritical CO2 (SC)), followed by the evaluation of the extract content in total phenolics and flavonoids, while the anaerobic digestion process for CH4 production followed.