Food waste biorefinery advocating circular economy: Bioethanol and distilled beverage from sweet potato

Abstract

The exponential growth rate of the global population has been causing a threat to finite resources and also increasing the amount of waste generated. The global quantitative food waste for tubers is 45% per year, which in Brazil would amount to 350,000 tons of sweet potato wasted annually. Food waste causes 10% of the emissions of greenhouse gases. In this work, food waste biorefineries are the proposed solution. Integrated processing via a combination of different technologies to produce both ethanol and distilled beverage was evaluated to valorize sweet potato waste profitably within the circular economy concept. No works concerning the integrated production of both products simulating different real market scenarios were found. Five different scenarios varying the production percentage of each product were evaluated. The higher the production of the distilled beverage, the more profitable the scenarios are. Economic results began to be positive when the production for sale of each product reaches 40%, plus 20% of ethanol for domestic consumption. The scenario with 80% of beverage production presented NPV of US$ 1,078,500.18, IRR of 51%, and discounted payback of 1.06 years. The sweet potato waste biorefinery is a sustainable model and contributes to the development of the agriculture and food sector by providing new businesses and consequent job creation. It also leads to the reduction of greenhouse emissions by producing renewable resources and marketable products, thus reaching the goals of the circular economy.