Food Waste as a Feedstock for Fungal Biosynthesis of Amylases and Proteases

Purpose: This work aimed the food waste (FW) valorization by the production of fungal enzymes in solid-state fermentation (SSF) and a hydrolysate with the potential to obtain products with high added value. Methods: An original bioprocess based on Rhizopus oligosporus cultured by SSF using medium consisting of FW, sugarcane bagasse (SCB), wheat bran (WB), and corn steep liquor (CSL) utilizing a cell-substrate recycling system was implemented. Results: The highest outcomes were achieved using FW as the main substrate and the strategy of one cell recycling round. The best condition for amylase production (260.9 U/g) was the blend FW 50%, SCB 10%, WB 40% supplemented with a salt solution. For the highest protease level (665.5 U/g) the same mixture was supplemented by 20% CSL. Hydrolysis of FW with the enzymatic extract from the best specified blend produced 47.10 g/L of reducing sugars. Conclusion: This bioprocess showed to be cost-effective, technically not demanding, and could be scaled up successfully for commercial goals. Graphical Abstract: [Figure not available: see fulltext.]