Eco-friendly protein-based materials for a sustainable fertilization in horticulture M. Jim  enez-Rosado a , J.F. Rubio-Valle b , V. Perez-Puyana b, * , A. Guerrero a , A. Romero b a Chemical Engineering Department, Escuela Polit ecnica Superior, Universidad de Sevilla, 41011, Sevilla, Spain b Chemical Engineering Department, Facultad de Química, Universidad de Sevilla, 41012, Sevilla, Spain article info Article history: Received 15 June 2020 Received in revised form 31 October 2020 Accepted 2 November 2020 Available online xxx Handling editor. Cecilia Maria Villas B^ oas de Almeida Keywords: Horticulture Matrices Micronutrients Plasticizer removal abstract Actually, there is a need to develop more sustainable novel techniques for incorporating fertilizers into crops. Researchers have proposed the controlled release of these fertilizers from biodegradable protein- based matrices. This technique must be optimized, as it involves a higher initial incorporation of micronutrients compared to that eventually retained by the matrix. The aim of this research was to improve the plasticizer removal stage in order to minimize the loss of micronutrient. To this end, three different aqueous media were used for the elimination of the plasticizer: water, ethanol and a mixture of both. The capacity of the media to remove the plasticizer and the retention of micronutrient by the matrices were evaluated. Furthermore, the mechanical, microstructural and functional properties of the matrices were analyzed. This work has showed that it is possible to optimize the process, obtaining matrices with higher micronutrient retention. © 2020 Published by Elsevier Ltd. 1. Introduction The world consumption of vegetables and fruits in 2018 has increased up to more than 1.1 billion tons. This great consumption has led to an increase in the world production of 22.9% over the last 10 years. In addition, the use of ornamental plants has also increased, making the whole horticultural industry to undergo an exponential rise in recent years. However, since the cropland has remained essentially constant, farmers have forced its over- exploitation in order to accomplish this increase in production (Organizaci on de las Naciones Unidas para la Alimentaci on y la Agricultura, 2018). All this has led to soil depletion due to the lack of enough time to regenerate the necessary nutrients and energy to support the new crops (Hazell and Wood, 2008). Thus, in order to avoid production decrease, farmers have opted for the use of fertilizers, which supply the soil with nutrients, making it available for reuse. However, the use of these fertilizers, typically used in large amounts due to their poor efficiency, are also responsible for some severe problems, such as subsoil and groundwater contamination (Shen et al., 2018). These problems have led to the search for alternative methods of incorporating fertilizers in soils, which can supply them in a more controlled way to avoid their excessive use (Feng et al., 2017). Several micronutrients are considered essential for the nutrition balance of plants, playing an important role in their growth and development. As examples, Fe is regarded as an essential substrate for the synthesis of chlorophyll (Kobayashi et al., 2019), Cu con- tributes plant growth by increasing its resistance to fungal and bacterial diseases (Yruela, 2005), Mn accelerates germination and maturity or Mo plays a direct role in the process of photosynthesis (Kaiser et al., 2005). Among them, Zn is particularly interesting since it participates in the metabolism of carbohydrates and pro- teins and is involved in gene transcription (Songkhum et al., 2018). The modern fertilizer market offers new methods of micro- nutrient administration. Among the possible techniques to be used, the modification of solubility can be highlighted, giving rise to products with a lower solubility, making the nutrient harder to leach out of the soil (Arslanoglu, 2019; Flores et al., 2006; Ray et al., 1993). Another alternative is based on the use of an external coating that allows to slow down the release of the nutrients due to the modification of the diffusion process due to the coating used (Abedi-Koupai et al., 2012). These coatings are based in the use of polymers that are biodegradable in farmland to avoid soil * Corresponding author. Departamento de Ingeniería Química, Universidad de Sevilla, 41012, Sevilla, Spain. E-mail address: vperez11@us.es (V. Perez-Puyana). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro https://doi.org/10.1016/j.jclepro.2020.124948 0959-6526/© 2020 Published by Elsevier Ltd. Journal of Cleaner Production xxx (xxxx) xxx Please cite this article as: M. Jim enez-Rosado, J.F. Rubio-Valle, V. Perez-Puyana et al., Eco-friendly protein-based materials for a sustainable fertilization in horticulture, Journal of Cleaner Production, https://doi.org/10.1016/j.jclepro.2020.124948