Ozone pretreatment of coffee husks (CH) was evaluated to generate hydrolysates for biogas production and to preserve cellulose of the solid phase for 2G ethanol production. Pretreatment variables included liquid-to-solid ratio (LSR), pH and specific applied ozone load (SAOL). Considering single-stage anaerobic digestion (AD), the highest methane production (36 NmL CH4/g CH) was achieved with the hydrolysate generated in the experiment using LSR 10 mL/g, pH 11 and SAOL 18.5 mg O-3/g CH, leading to 0.064 kJ/g CH energy recovery. Due to the presence of toxic compounds in the hydrolysate, the addition of powdered activated carbon (4 g/L) to the reactor enhanced biogas production, leading to 86 NmL CH4/g CH yield and 0.58 kJ/g CH energy recovery. When two-stage AD was applied, methane production resulted in 49 NmL CH4/g CH, with additional 19 NmL H-2/g CH production, resulting in a net 0.26 kJ/g CH energy recovery.