Bioprocessing to upcycle agro-industrial and food wastes into high-nutritional value animal feed for sustainable food and agriculture systems

The ever-increasing demand of food and feed along with enormous amounts of losses, wastes, and discards from agricultural and food supply chain have caused numerous socioeconomic and sustainability challenges. Many of these agro-industrial by-products and food wastes have low nutritional and economic value. Examples of these types of feedstocks include biofuel co-products (e.g. distiller grains, sugarcane bagasse), agro-industrial processing wastes (e.g. oil seed meal, soybean hulls, sugar beet pulp), crop residues (e.g. wheat straw, corn stover) and fruit and vegetables discards. Using feed grade fungi, yeast, bacteria, and enzymes to process (bioprocess) low-valued feedstocks improves protein quality, degrades lignin and improves utilization of dietary fiber for energy, improves phosphorous digestibility, and reduces anti-nutritional factors (e.g., mycotoxins) to permanently change the composition of the feedstocks and improve their feeding value for livestock, and therefore, achieving a sustainable food supply system with reduced carbon, nitrogen, and phosphorus footprint. The purpose of this paper is to provide a systematic review of the challenges and potential use of current agro-industrial and food wastes as animal feed ingredients using bioprocessing to improve their feeding value. Highlights from three case studies on bioprocessing of corn-distiller grains, oil seed meals, crop/wood residues with fruit and vegetable discards will be discussed relative to changes in feeding value and contributions toward achieving a more circular and sustainable food supply chain.