Rhizopus oryzae as Fermentation Agent in Food Derived Sub-products

Abstract

The present research describes the use of Rhizopus oryzae as bioconversion agent of different agro-industrial by-products (fruit wastes, olive pulp cake, coffee grounds and potato peels) by solid state fermentation at different experimental conditions to enhance their value as animal feed. Results showed that R. oryzae grows better at fruit wastes than in other by-products. Fermentation process produced a protein and fat rich mycelia [respectively, 7.8 ± 1.2 and 9.0 ± 0.4% of dry matter (DM)] and reduced the carbohydrates content of considered by-products from 60.6 ± 0.4 to 40.1 ± 0.3% DM in 3 days. Supplementation with different nitrogen sources increases dramatically the protein concentration in the mycelia up to 46.8 ± 0.7% of DM. After fermentation, amino acid profile changed in the fermented product, with significant enrichment of several essential amino acids like valine, leucine, threonine, isoleucine and arginine and lower aspartate concentration. In conclusion, obtained product can be a high value alternative for animal feed.