Co-management of agro-industrial wastes by solid-state fermentation for the production of bioactive compounds

Agro-food industries face the challenge of re-using their wastes following the circular economy concept. The cobioprocessing of wastes produced by different agro-food industries located in the same region can be a suitable strategy for the valorization of these wastes. This work evaluated the use of mixtures of wastes from wineries, olive mill and breweries to produce lignocellulolytic enzymes and antioxidant compounds by Aspergillus niger under solid-state fermentation (SSF). The SSF of a mixture of brewery spent grain with crude and exhausted olive pomace led to the highest values of enzymatic activity (xylanase, 837 U/g, cellulase, 87 U/g; beta-glucosidase, 254 U/g), being higher than enzymes activities per mass of total substrates. The highest antioxidant activity was achieved after 1 day of fermentation, being 2.3-fold higher in comparison to the unfermented wastes. SSF allowed the co-management of agro-industrial wastes from different industries.