Characteristics of food processing wastes and their use in sustainable alcohol production

Food processing operations produce large amounts of waste that are rich in nutrients, and although these wastes are utilized to produce value-added products to some extent, the majority of the waste is discarded. This paper provides a comprehensive review of the characteristics of food processing waste for micro-and macro-nutrient composition, and utilization of these materials in alcohol production. The feasibility of producing alcohols, mainly ethanol and butanol, was investigated while identifying the research gaps and suggesting future directions for food processing waste utilization. Ethanol and 1-butanol are the most studied alcohols produced by fermentation of food processing wastes. Methanol is used to a much lesser extent as fuel and produced using chemical conversion methods. Propanol and isobutanol from fermentation of food processing waste are gaining interest more recently, and there are fewer published articles on these products. Alcohols have high market demand as fuels and industrial solvents. Effective utilization of food processing wastes in alcohol production can significantly affect the production economics by not having a need to grow crops for raw materials or acquiring biomass at a high cost. Although theoretically alcohol production from food processing waste appears to be feasible, the technology still has to overcome several constraints.