Grape pomace, the solid residue from winemaking, is produced in large seasonal quantities and represents a challenge for sustainable waste management due to its elevated lignin concentration, which severely limits its biodegradability in anaerobic digestion. Its potential as a feedstock for bioenergy production remains underexploited, largely because of this recalcitrant fraction. This study investigates an integrated thermochemical and biological conversion route aimed at enhancing biogas production from grape pomace. The biomass was subjected to mild hydrothermal treatment under pressurized conditions to restructure its lignin matrix, followed by anaerobic digestion to assess biogas yields. The effects of temperature and solid yield on lignin content and bioconversion efficiency were analyzed. Results show that thermochemical pretreatment increases the overall lignin content while inducing morphological changes that improve its fermentability. Notably, pretreated samples produced higher-than-expected biomethane volumes up to 29%, suggesting the partial degradation of the modified lignin reduces its recalcitrance to bioconversion. By comparison with literature, a generalized correlation of biomethane yield with treatment temperature was discovered for different lignocellulosic biomasses, showing a maximum at around 130 °C. The findings confirm the viability of combining mild thermochemical treatment with anaerobic digestion as a strategy to valorize grape pomace, aligning with circular economy principles.
Biogas production through combined thermochemical and biochemical processing of grape pomace
Polchri L.Methodology
;Mazzocchi M.Methodology
;Ammendola P.Writing – Review & Editing
;Raganati F.Writing – Review & Editing
;Miccio F.
Conceptualization
2026
Abstract
Grape pomace, the solid residue from winemaking, is produced in large seasonal quantities and represents a challenge for sustainable waste management due to its elevated lignin concentration, which severely limits its biodegradability in anaerobic digestion. Its potential as a feedstock for bioenergy production remains underexploited, largely because of this recalcitrant fraction. This study investigates an integrated thermochemical and biological conversion route aimed at enhancing biogas production from grape pomace. The biomass was subjected to mild hydrothermal treatment under pressurized conditions to restructure its lignin matrix, followed by anaerobic digestion to assess biogas yields. The effects of temperature and solid yield on lignin content and bioconversion efficiency were analyzed. Results show that thermochemical pretreatment increases the overall lignin content while inducing morphological changes that improve its fermentability. Notably, pretreated samples produced higher-than-expected biomethane volumes up to 29%, suggesting the partial degradation of the modified lignin reduces its recalcitrance to bioconversion. By comparison with literature, a generalized correlation of biomethane yield with treatment temperature was discovered for different lignocellulosic biomasses, showing a maximum at around 130 °C. The findings confirm the viability of combining mild thermochemical treatment with anaerobic digestion as a strategy to valorize grape pomace, aligning with circular economy principles.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
