Agro-food wastes for the release of phyto-chemicals and the production of enzymes by solid state fermentation using pleurotus ostreatus

The agro-food wastes represent a very important resource to recover chemical compounds with high added value that can be used in several industrial sectors and to the energetic production by biomass. This is a good method to value the agro-food wastes that are often undervalued. The hydrolitic demolition by lignocellulosic enzymes is one of the most studied approach for recovering phyto-chemicals from the cell wall of plants. Enzymes are perfect to this role, because they can be used in blind conditions resulting cheap and profitable. In this study, the concentration of reducing sugar (glucose) and total polyphenols (catechin), released in solution after the hydrolysis with lignocellulosic enzymes, were determined. The enzymes (extract enzymes) used are previously obtained, by growing the fungus Pleurotus ostreatus in solid state fermentations in presence of four separated agro-food wastes: grape stalks, grape seed, wheat straw and wheat bran. For the hydrolysis, the same biomass was used as substrates doing different combinations of substrate and enzymes extract (from different sources). The enzyme extracts from grapes stalks and wheat bran promoted the release of reducing sugars that were naturally rich in cellulase, pectinase xylanase activities. The wheat bran was the only matrix able to be hydrolyzed by all the enzyme extracts, probably due to the fact that its arabinoxylan structures are hydrolysable from the xylanase activities found in all the enzyme extracts. The increases on the polyphenols concentration during the hydrolytic reaction in oenological wastes were observed in the matrices rich in polyphenols such as grape seed and grape straw, even if the enzyme from the wheat bran was able to increase the content of polyphenols of 84 % compared to the initial one.