Valorization of horse chestnut burs to produce simultaneously valuable compounds under a green integrated biorefinery approach Patricia Gullón a, ⁎, Beatriz Gullón b, ⁎, Abel Muñiz-Mouro c , Thelmo A. Lú-Chau c , Gemma Eibes c a Laboratory of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigaciones Marinas (IIM-CSIC), Eduardo Cabello, 6, 36208 Vigo, Pontevedra, Spain b Department of Chemical Engineering, Faculty of Science, University of Vigo (Campus Ourense), As Lagoas, 32004 Ourense, Spain c CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain HIGHLIGHTS • Horse chestnut burs (HCB) was ex- plored as a potential source of valuable biocompounds • 11 phenolics from HCB extracts were identified by UPLC-DAD-ESI-MS • Structural profile and thermal stability of HCBE were reported by the first time • Antioxidants-free solid was exploited for obtaining glucose and lignin • HCB based biorefinery with zero-waste could contribute to sustainable development GRAPHICAL ABSTRACT Integrated biorefinery approach to valorize HCB into antioxidants, glucose and lignin. abstract article info Article history: Received 9 April 2020 Received in revised form 28 April 2020 Accepted 29 April 2020 Available online 4 May 2020 Editor: Frederic Coulon A biorefinery scheme for the valorization of horse chestnut biowastes (a municipal solid waste) into added value bioactive compounds is proposed in this work. The bur fraction of horse chestnut was evaluated as a novel and cheap renewable feedstock to obtain valuable compounds suitable for their use in industrial applications. The in- tegrated valorization scheme comprised an initial hydroethanolic extraction of antioxidant compounds (opti- mized through surface response methodology), the alkaline delignification of the exhausted solid to obtain a lignin-enriched fraction, and the enzymatic digestibility of the remaining cellulose fraction to produce ferment- able sugars. In addition, the structural characterization of the extract by FT-IR and TGA was performed, and the analysis by UPLC-DAD-ESI-MS allowed the tentative identification of eleven antioxidant phenolic compounds. The application of this multiproduct valorization approach led to the production of 13 kg antioxidant extracted compounds, 33.2 kg lignin and 14.5 kg glucose per each 100 kg of horse chestnut burs, which demonstrates the great potential of this residue as a biorefinery substrate. © 2020 Elsevier B.V. All rights reserved. Keywords: Horse chestnut Biowastes Bioactive compounds Integral valorization Platform chemical Chemical characterization Science of the Total Environment 730 (2020) 139143 ⁎ Corresponding authors. E-mail addresses: pgullon@uvigo.es (P. Gullón), bgullon@uvigo.es (B. Gullón). https://doi.org/10.1016/j.scitotenv.2020.139143 0048-9697/© 2020 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv