Advances in Agroindustrial Waste as a Substrate for Obtaining Eco-Friendly Microbial Products

Recycled agroindustrial waste has been of great interest during the last decade as a low-cost and sustainable substrate for fermentation processes. The types of products, yields, and potential applications depend mainly on the waste composition, which varies in terms of proteins, carbohydrates, and/or polyphenolic compounds. The most commonly reported microbial products are enzymes, pigments, biosurfactants, antibiotics, and phenolic compounds for different industrial applications. Advances in research on novel wastes as nutrient sources and the optimization of fermentation processes can help these materials transition from laboratory applications to an industrial level. This review explores reports published in the last five years (2017–2022) on different types of agroindustrial waste and their utilization in the production of useful microbial products. The present scenario and future scope of agroindustrial waste as substrates for submerged and solid-state fermentation processes are also discussed. The information was analyzed considering two main topics: (i) agroindustrial waste as substrates for fermentation processes and (ii) high-added value products obtained by microbial conversion. This review contributes to future research endeavors to discover the key factors that will allow us to reach the market with sustainable microbial products.