| Popis: |
By-products of the food industry are abundant sources for the production of 2nd generation ethanol. To be used for bioethanol production, these materials must be pretreated. Biological methods, such as solid-state fermentation, have been extensively studied for this purpose. In this work, grape pomace, sugar beet pulp, and brewer's spent grains were biologically treated with the white rot fungus Trametes versicolor under solid- state fermentation conditions for 15 days to produce sugar-rich hydrolysates. In addition, substrates were fully chemically analysed before and after fermentation (lignin, cellulose, hemicellulose, proteins, lipids, total and simple polyphenols, total reducing sugars, and simple sugars). While grape pomace treatment resulted in a 2-fold decrease in the concentration of total reducing sugars (from 22.27 mg/gDM to 11.34 mg/gDM), a 5.73-fold increase in total reducing sugars was observed with brewer's grains (from 2.27 mg/gDM to 15.59 mg/gDM). The highest increase in total reducing sugars (25.33-fold) was observed in sugar beet pulp (from 1.39 mg/gDM to 14.83 mg/gDM). Of all the analysed simple sugars (glucose, fructose, xylose, arabinose, ribose) in the sugar hydrolysate obtained from sugar beet pulp, glucose was found to be represented in the highest amount (ɣGLC = 0.55 g/L). The solid-state fermentation process should be optimised and the methods for sugar concentration in the obtained hydrolysate should be further developed so that it can be used for bioethanol production. |
