Bioconversion of grape pomace waste into suitable alternative feed for ruminants with Pleurotus cornucopiae and Ganoderma resinaceum via solid-state fermentation bioprocess

Effect of Fungal Solid-State Fermentation on the Profile of Phenolic Compounds and on the Nutritional Properties of Grape Pomace

“…Research reports that white-rot fungi can efficiently degrade lignocellulosic biomass to carbon dioxide and water because they have the ability to produce extracellular enzymes that catalyze the biochemical reactions involved in the degradation of the lignocellulosic complex [11]. In this study, the activity of lignolytic enzymes (laccase, manganese peroxidase; MnP) and hydrolytic enzymes (βglucosidase, xylanase, cellulase, invertase) was measured during the SSF processes in jars and tray bioreactor (1-10 and 15 days of SSF).…”

“…According to literature, the ash content in GP is in the range of 3 -9.3%, the protein content in the range of 7 -14.41% and the fat content in the range of 6.44 -10.47% [10,11,13,44,45].…”

“…The increase in crude protein content can be attributed to the production of enzymes and/or mycelia by the fungus used [46,47]. The results of Abid et al [11] show an increase in crude protein content from 10.3% to 12.8% and 12.9% after four and eight days of SSF of GP with Pleurotus cornucopiae and Ganoderma resinaceum, while ash content also increased from 9.3% to 14.8% and 16.2%.…”

“…However, not all phenolic compounds from grapes are extracted into the wine during production, leaving about 70% of these bioactive compounds in GP [3]. In order to utilize the bioactive compounds and their benefits, many researchers deal with finding alternative uses of GP, such as obtaining extracts with antioxidant properties, composting and use as biomass for energy production, use in the sustainable production of food enriched with polyphenols and fiber, use in encapsulation techniques, use as fermentation substrates and feed for ruminants [6,[10][11][12][13][14].…”

“…In addition to the fact that a large proportion of phenolic compounds remain in GP after winemaking, it is characteristic not only of GP but of all plant matrices that some phenols are 2 covalently bound to cellulose, hemicellulose, lignin, pectin and structural proteins in the lignocellulosic structure, which gives them the property of insolubility and low extractability. Numerous methods are used for the degradation of lignocellulosic biomass and for extraction of bioactive compounds, but one biological technique that is attracting increasing attention and appears promising for modifying the lignocellulosic complex and releasing soluble phenols is solid-state fermentation (SSF) [6,11]. SSF is the cultivation of microorganisms on a solid substrate without the presence of free water and offers an alternative for the production of various enzymes, bioactive compounds and other valuable components at low production costs [15,16].…”