Citation: Alves-Ferreira, J.; Duarte, L.C.; Fernandes, M.C.; Pereira, H.; Carvalheiro, F. Cistus ladanifer as a Potential Feedstock for Biorefineries: A Review. Energies 2023, 16, 391. https://doi.org/10.3390/en16010391 Academic Editors: Gabriella Fiorentino and Diego Luna Received: 2 November 2022 Revised: 17 December 2022 Accepted: 22 December 2022 Published: 29 December 2022 Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Review Cistus ladanifer as a Potential Feedstock for Biorefineries: A Review Júnia Alves-Ferreira 1,2,3,4 , Luís C. Duarte 1 , Maria C. Fernandes 2,5 , Helena Pereira 3 and Florbela Carvalheiro 1, * 1 LNEG—Laboratório Nacional de Energia e Geologia, Unidade de Bioenergia e Biorrefinarias, Estrada do Paço do Lumiar, 22, 1649-038 Lisboa, Portugal 2 CEBAL—Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo, Instituto Politécnico de Beja (IPBeja), Rua Pedro Soares, S.N.-Campus IPBeja/ESAB, Apartado 6158, 7801-908 Beja, Portugal 3 CEF—Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisboa, Portugal 4 Instituto Politécnico de Beja, Escola Superior Agrária de Beja, Rua Pedro Soares, 7800-295 Beja, Portugal 5 Mediterranean Institute for Agriculture, Environment and Development & CHANGE—Global Change and Sustainability Institute, CEBAL—Centro de Biotecnologia Agrícola e Agro-Alimentar do Alentejo, 7801-908 Beja, Portugal * Correspondence: florbela.carvalheiro@lneg.pt Abstract: Cistus ladanifer (rockrose) is a widespread shrub species in the Mediterranean region well known due to its production of labdanum gum, especially in the hot season. Its leaves and branches can be subjected to different extraction and distillation processes to produce various types of extracts. The natural extracts of C. ladanifer have several applications, especially in the perfumery and cosmetics sector. C. ladanifer extracts, in addition to presenting interesting odoriferous properties, are also known for their bioactive properties, such as antioxidant and antimicrobial. Use of this species in animal feed or phytostabilisation of mining areas has also been successfully applied. On the other hand, the lignin and polysaccharides that are the major fractions from Cistus residues can be relevant sources of high-value products in a biorefinery framework. Recently, it has been reported that the residues obtained from the essential oil industry can sustain production of significant amounts of other marketable products, namely phenolic compounds, oligomeric and monomeric sugars, lignin, and lactic acid. All these applications show the potential of C. ladanifer as a raw material to be fully valued in a biorefinery context, contributing to important revenues and generating an associated marketable biobased product portfolio. Keywords: added-value products; bioeconomy; biofuels; essential oils; integrated upgrade; rockrose 1. Introduction Cistus ladanifer L. (crimson-spot rockrose) is a wild perennial shrub species of the Cistaceae family and the Cistus genus that is mainly distributed in Mediterranean countries, such as France, Greece, Spain, Portugal, Morocco, Algeria, and Cyprus [1–6]. The C. ladanifer species includes three subspecies: ladanifer ( ... ), africanus (Dans), and sulcatus (Demoly). The subsp. ladanifer is mainly distributed in the Iberian Peninsula, France, and northern Africa; the subsp. sulcatus is endemic to southwestern Portugal along the coastal cliff tops of Costa Vicentina; and the subsp. africanus is commonly found in northern Africa and also spread in southern Spain [7,8]. Subsp. ladanifer has an erect habit, generally with linear–lanceolate and lanceolate leaves [5,9]; subspecies sulcatus is a prostrated habit shrub (50 cm) when it grows near the sea or up to 200 cm and erect when protected from the wind, with white flowers and sessile leaves, generally elliptical or oblanceolate, with accentuated nervures in the upper surface [9]; and subsp. africanus has leaves with an apparent petiole, lanceolate–elliptic, or oblong to linear—generally Energies 2023, 16, 391. https://doi.org/10.3390/en16010391 https://www.mdpi.com/journal/energies