Conversion of grape pomace into fungal biomass: a study of Pleurotus cultivation for a sustainable agro-residue management

Federico Puliga ¹, Veronica Zuffi ¹, Dario Mercatante ¹, Maria Teresa Rodriguez-Estrada ¹, Santiago Sanchez-Cortes ², Ornella Francioso ¹, Alessandra Zambonelli ¹

Department of Agricultural and Food Sciences, University of Bologna, Viale G. Fanin 40‐50, 40127 Bologna, Italy. ¹, Instituto de Estructura de La Materia, IEM‐ CSIC, Serrano, 121, E‐28006 Madrid, Spain. ²

Grape production, with an annual output of approximately 80.1 million tons, generates substantial agricultural waste, particularly grape pomace, a by-product rich in bioactive compounds. Moreover, its reuse is strongly recommended since storage or direct application can lead to environmental issues. This study explores the feasibility of using exhausted grape pomace, both alone and in combination with anaerobic digestate, as substrates for cultivating Pleurotus mushroom species. Grape pomace's rich composition in fiber, lipids, sugars, proteins, and phenolic compounds makes it a promising substrate. Elemental analyses revealed high carbon (46%) and nitrogen (2.5%) content, along with greater levels of macro and microelements (P, Ca, Mg, Fe) compared to conventional substrate. Fourier transform infrared spectroscopy (FTIR) identified aliphatic groups associated with fatty acids from the seeds and polysaccharide bands typical of the seedless part of grape pomace. Fatty acid evaluation confirmed partial glycerides with linoleic acid content exceeding 62%, while the phenolic composition analysis highlighted a predominance of bound phenols. These chemical characteristics led to a significant increase in production for all tested Pleurotus species, with statistical differences observed in the fresh weights of mushrooms grown with grape pomace compared to those grown without it. The mixture with digestate gave the most promising results, likely due to the balanced pH values around neutrality. Lastly, FTIR and Surface-enhanced Raman Scattering (SERS) spectra of the fruiting bodies grown on different substrates were comparable, indicating consistent quality characteristics in the mushrooms. These results provide attractive perspectives for both more sustainable grape pomace management and for the improvement of mushroom cultivation efficiency.

Main author career stage: Professor / Permament researcher

Contribution type: Talk

First choice session: 6. Plants, Fungi and Society

Second choice session: 6. Plants, Fungi and Society