Bioethanol production from food wastes rich in carbohydrates

The inefficient food processing and food leftover management strategies often lead to the wastage of untapped carbohydrate-rich feedstocks. The conversion of these feedstocks into bioethanol can mitigate the emission of greenhouse gases (GHGs) while providing a sustainable and eco-friendly method for disposing of food wastes. In light of the above, the current review scrutinizes various types of food wastes (homogeneous and heterogeneous) and pretreatment methods (physical, chemical, physicochemical, and biological) for their valorization into bioethanol. The main constraints to commercial production of food-waste-derived bioethanol, that is, the requirement for sterilization and collection of feedstocks, are also discussed. The former issue can be addressed by developing an optimized solid-state fermentation process. Employing selective conditions to enrich bioethanol-producing microorganisms can increase the feasibility of this process configuration while inhibiting ethanol-consuming strains. The feedstock collection issue can be minimized by determining the hot spots that are in the vicinity of the large food processing sites.