Valorization of Agro-Industrial Wastes and Residues through the Production of Bioactive Compounds by Macrofungi in Liquid State Cultures: Growing Circular Economy

Abstract

Vast quantities of side streams produced worldwide by the agricultural and food industry present an environmental challenge and an opportunity for waste upcycling in the frame of the circular bioeconomy. Fungi are capable of transforming lignocellulosic residues and wastes into a variety of added-value compounds with applications in functional food products, pharmaceuticals, chemicals, enzymes, proteins, and the emerging sector of nutraceuticals. The liquid state culture of fungi is an efficient and potentially scalable and reproducible biotechnological tool that allows the optimized production of fungal metabolites. Particularly, the utilization of agro-industrial by-products, residues, and wastes as a substrate for the liquid culture of macrofungi is suggested as an attainable solution in the management of these streams, contributing to climate change mitigation. This review presents recently published literature in the field of liquid state cultures of macrofungi using agro-industrial side streams, the different substrates, methods, and factors affecting their growth and metabolite production, as well as their applications, focusing on the variety of natural valuable compounds produced.