Coffee production worldwide has grown by almost 200% since 1950 due to increased demand, being the world's most important traded commodity after oil and the second most popular beverage after water, with more than 500 billion cups of coffee consumed annually (Visser and Dlamini in Sustainability 13:6558, 2021). Colombia is the third largest producer and exporter of coffee worldwide (Garcia-Freites et al. in Biomass Bioenerg 140, 2020). Due to its nature, the coffee sector produces a large amount of waste throughout its production chain, with ~ 0.9 kg of accumulated waste per 1 kg of coffee cherries harvested, equivalent to about 4 thousand tons per year for Colombian production (Garcia-Freites et al. in Biomass Bioenerg 140, 2020). Among the variety of remnants or by-products generated are those from plant pruning and coffee processing (Mendoza Martinez in Biomass Bioenergy 120:68–76, 2019, Hejna in Waste Manage 121:296–330, 2021). This diversity of by-products represents a varied source of molecules suitable for utilisation in different industries in a promising way to solve the environmental and economic impacts represented by the disposal of these remnants. This review aims to present the value and utilisation of these by-products in different industries in which several articles published on the subject were compiled and discussed, with utilisation in the food, agriculture, biorefinery and bioplastics industries. Based on the review presented, it is discovered that the by-products of the coffee industry offer many valuable options developed by scientists to generate value in the coffee production chain that contribute to environmental protection with a promising approach in search of a circular economy. Graphical Abstract

In this research, the types of hemicellulose that predominate in the leaves and tops of the three most cultivated varieties (CC 8475, CC 8592, V 7151) of sugarcane (Saccharum officinarum L.) in Valle del Cauca, Colombia were determined. Hemicellulose analyses were performed after delignification with sodium chlorite and extraction with 18% NaOH and 24% KOH containing 0.26 M NaBH4. The main components of hemicellulose were identified via FTIR and NMR spectroscopy, and monomeric sugars were identified via HPLC. Hemicellulose A composed of arabinoxylans, glucomannans and arabinogalactactans and hemicellulose B primarily composed of arabinoxylans were extracted. The hemicelluloses of the Colombian varieties were more stable against heat than those of the Venezuelan variety. The results of this project allowed discovery of the potential use of agricultural sugarcane residues for bioethanol production because they have a holocellulose content of more than 60%.

En Colombia se producen alrededor de 9 millones de toneladas de residuos de la cosecha de la caña de azúcar por hectárea cada año, que no han sido valorizados hacia ningún tipo de producto. Es necesario conocer su composición, en especial el contenido de hemicelulosas, para dilucidar el proceso para obtener los monosacáridos de éstas y aislarlos eficientemente. Para separar las hemicelulosas puras, se estudiaron cinco procesos de extracción a partir de las hojas y cogollos de las variedades de caña de azúcar CC 8592, CC 8475 y V 7151. Después de evaluar la eliminación de ceras con etanol y mezclas de cloroformo-metanol, los residuos se expusieron a diferentes concentraciones de peróxido de hidrógeno y clorito de sodio acidificado para lograr su deslignificación. Adicionalmente, se desarrollaron procedimientos de extracción con hidróxido de sodio e hidróxido de potasio, y de precipitación. El método que logró el mayor rendimiento fue el de desceración con metanol-cloroformo y deslignificación con clorito de sodio y borohidruro de sodio, con un rango de recuperación entre 0.20-0.34 g hemicelulosas /g residuo seco en las variedades estudiadas.