Food waste biorefinery advocating circular economy: Bioethanol and distilled beverage from sweet potato Caroline Trevisan Weber * , Luciane Ferreira Trierweiler , Jorge Ot  avio Trierweiler Group of Intensification, Modeling, Simulation, Control and, Optimization of Process (GIMSCOP), Department of Chemical Engineering, Federal University of Rio Grande Do Sul (UFRGS), Rua Engenheiro Luiz Englert S/n, Pr edio 12204, Porto Alegre, Rio Grande do Sul, 90040-040, Brazil article info Article history: Received 15 October 2019 Received in revised form 16 April 2020 Accepted 17 April 2020 Available online 18 May 2020 Handling Editor: Cecilia Maria Villas B^ oas de Almeida Keywords: Sweet potato waste Biorefinery Bioethanol Distilled beverage Circular economy 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 so- lution. 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. © 2020 Elsevier Ltd. All rights reserved. 1. Introduction An exponential growth rate of the global population has been a major challenge causing a significant threat to finite resources. At present, more than 90% of our energy needs and the majority of material demand are held by fossil-based reserves that eventually emit greenhouse gases (Mohan et al., 2016a). With the present consumption rate of fossil fuels, the available reserves may run out soon. Therefore, the requirement of alternative resources to meet our energy and material needs that are renewable and sustainable is essential (Hemalatha et al., 2019). The growth of the global population also has, as a consequence, the high amount of waste generated. It is estimated that about 1.3 billion tons of foods are lost or wasted globally, representing approximately one-third of the edible parts of food produced for human consumption (FAO, 2019). Food waste caused 10% of the emissions of greenhouse gases in the period 2010e2016 (IPCC, 2019). Brazil is one of the largest pro- ducers of agricultural and animal commodities, which produces large amounts of residues and wastes (Forster-Carneiro et al., 2013). Waste is a crucial feedstock and renewable resource with a well- defined role to play in the framework of circular bioeconomy (Mohan et al., 2019). In this context, emerge the concept of food waste biorefineries, which can be employed for the production of biofuels, targeting economic viability and sustainability within the circular economy concept (De Jong et al., 2012; Mohan et al., 2016b). In the last few decades, there has been a trend in the production of biofuels as a need for decarbonizing our economy to mitigate climate change and to restrain the depletion of fossil resources (Papadaskalopoulou et al., 2019). Bioethanol is one of the most common commercial biofuels (Zhang et al., 2020). Sweet potato (Ipomoea batatas) has been considered a promising raw material for ethanol production, as it has a higher starch yield per unit land cultivated than grains (Lareo and Ferrari, 2019). The Brazilian pro- duction of sweet potatoes is the 16th in the world ranking, with a * Corresponding author. E-mail addresses: caroltw@enq.ufrgs.br (C.T. Weber), luciane@enq.ufrgs.br (L.F. Trierweiler), jorge@enq.ufrgs.br (J.O. Trierweiler). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro https://doi.org/10.1016/j.jclepro.2020.121788 0959-6526/© 2020 Elsevier Ltd. All rights reserved. Journal of Cleaner Production 268 (2020) 121788