Research Article Received: 27 November 2018 Revised: 5 May 2019 Accepted article published: 4 May 2019 Published online in Wiley Online Library: (wileyonlinelibrary.com) DOI 10.1002/jsfa.9847 Whole unripe plantain (Musa paradisiaca L.) as raw material for bioethanol production Leonardo A Alonso-Gómez, a Erick Heredia-Olea, b Sergio O Serna-Saldivar b and Luis A Bello-Pérez a* Abstract BACKGROUND: The use of byproducts such as rejected plantain with final disposition problems and conversion processes with ‘green’ technologies are important research topics. Bioethanol production from crops with a high content of fermentable sugars is an alternative to that from traditional crops (corn and sugar cane). The aim of this work was to study the use of whole (peel and pulp) unripe plantain (WP) for bioethanol production. RESULTS: Lab-scale liquefaction and saccharification of both materials released mainly three carbohydrates, glucose (9.02 mg g -1 ), maltose (0.45 mg g -1 ) and xylose (0.25 mg g -1 ). The WP saccharification required the use of pectinase and cellulase because of the high amounts of pectin and cellulose associated with the peel. Fermentation for 11 h produced similar ethanol concentration for both samples, but at the end of fermentation (32 h), the ethanol production was higher in the WP (58.6 mL L -1 ) compared with the plantain pulp (PP) (45.5 mL L -1 ). The theoretical ethanol yield was lower with WP (67%) than with PP (90%). CONCLUSION: WP can be an alternative raw material for bioethanol production. © 2019 Society of Chemical Industry Keywords: bioethanol; hydrolysis; fermentation; starch; cellulose; plantain INTRODUCTION Increasing concerns over environmental pollution have led to a growing focus on the development of renewable energy sources. Biofuels, especially bioethanol, have advantages such as being renewable and domestically produced. These practices encourage rural economies and the creation of new jobs in areas where employment opportunities are scarce. The carbon dioxide released by a vehicle when ethanol is burned is offset by the car- bon dioxide captured when the feedstock crops are grown. Brazil and the USA are by far the major producers of bioethanol, and these countries already include 10 – 27% ethanol in their standard fuels by law. 1 The USA is the world’s largest producer of ethanol, with a yearly production of 59.6 × 10 6 m 3 in 2016. 1 Together, the USA and Brazil produce 85% of the world’s ethanol. The majority of US ethanol is obtained from corn, while Brazil primarily uses sugar cane. 1 There are other potential crops for producing ethanol, and their feasibility mainly depends on geographical location, crop availability and social, economic and cultural conditions of each country. Lignocellulosic biomasses such as agricultural wastes and dedicated crops are potential promising natural sources for the next generation of bioethanol production. Nevertheless, the logistics of ‘just in time’ harvesting and the pretreatment and enzymatic hydrolysis plus the use of natural or genetically engineered ethanologenic microorganisms capable of ferment- ing both pentose and hexose are the major obstacles faced by second-generation bioethanol refineries. On the other hand, simultaneous saccharification and fermentation have been reported in lignocellulosic materials, but thermotolerant strains should be used; 2 also, physical and chemical pretreatment to produce the fermentable sugars was reported as an alternative method to enzymes. 3 To solve these cellulosic technology bottle- necks, novel science and efficient technologies need to be devised and improved. 4 The alternative raw materials that are currently being consid- ered for first-generation bioethanol production in commercial large-scale biorefineries are mainly sugar beet juice, cassava, sweet sorghum, sorghum grain and wheat. The favorable resource for the region of southeastern Europe is sugar beet, 5 and 30% of consumed bioethanol in Europe is produced from sugar beet. 6 In China, five industrial plants processing non-food crops have been established in Guangxi, Guangdong, Hainan, Zhejiang and Jiangxi respectively. All these plants use cassava as feedstock, with a total production capacity of 0.85 Mt. 7 There are initiatives in many countries for the implementation of sorghum as a raw material for ethanol; the Rusni ethanol production unit located in the Medak district of Andhra Pradesh in India is the world’s first sweet sorghum-based ethanol production distillery, with a total capacity of 40 kL day -1 . 8 Nevertheless, the increasing demand for ∗ Correspondence to: LA Bello-Pérez, Instituto Politécnico Nacional, Yautepec, Mexico. E-mail: labellop@ipn.mx a Instituto Politécnico Nacional, Yautepec, Mexico b Centro de Biotecnología-FEMSA, Tecnológico de Monterrey, Monterrey, Mexico J Sci Food Agric (2019) www.soci.org © 2019 Society of Chemical Industry