Extreme environments often appear uninhabitable, yet halophyte plants have evolved unique adaptations to thrive in saline ecosystems. Their physiological resilience makes them a promising resource for sustainable applications. Beyond natural roles, halophytes have been explored for food, feed, pharmaceuticals, and bio-based materials. The HALO-TEX project takes this further by transforming halophyte biomass into eco-friendly industry-demanded materials.
What are Halophytes?
Severe environments of diverse kinds can be found across the globe, from frozen poles and torrid deserts to acidic volcanic terrains and dark oceanic with major pressure levels. Those may seem inhabitable conditions, but life always makes its ways through.
An outstanding example of evolution and adaptation to extreme environments are halophyte plants. Halophytes are salt-tolerant plants that have evolved physiologically and biochemically differently as from glycophyles -main number of in-land plants-. They can be found in near-shore shallows, estuaries, mangrove forest, coastal salt marshes, lasty lakes and saline deserts (Flowers et al., 2015). Their physiology is focused on adaptation. Their capacity to regulate ion-exchange and io-exclusion processes allows them to transpire water and fix carbon without NaCl precipitation in the leaves. This fact makes halophyte metabolic mechanisms a hot research topic; and could be the potentially initiator of applications to genetically modify other kinds of crops in order to enhance re-vegetation of certain terrains (Colmer et al., 2006).
While saline habitats occur naturally, they are more common in salt-water coastal areas; and those located at inland regions are distributed irregularly. In Europe, most of the continental coast is inhabited by salt-tolerant plants, however, the major refugial areas for halophytes have been identified over the Mediterranean coasts. This fact is strongly related to the colonization of southern areas by plant and animal species repeatedly forced to retreat from Glaciations (Weising et al., 2007). Also, halophytes cover a great region in north Europe at the Caspian Sea and the North of the Black Sea (Díte et al., 2023).
Use of Halophytes in HALO-TEX
Different applications of halophytes have been described in the last decade: biomass production and feeding to ruminants during the beginning of autumn (Norman et al., 2012), vegetable oil and protein seed meat production for the food industry (Glenn et al., 2012), source of complex chemical precursors such as phenols for the pharmaceutical and food industry (Lopes et al., 2021), precursor for medicinal and nutritional extracts (Ksouri et al., 2011).
HALO-TEX will provide safe and competitive solutions to produce high-value chemicals and sustainable fibres from halophyte plants. More specifically, Sea Aster (tripolium pannonicrum) and Sarcocornia will be used to fabricate cellulose fibres by a biorefinery approach, as well as biochemicals for textile additives and cosmetics. This approach represents an attractive course for the revalorization of biomass with a circular multi-product aim, which contributes to the European Green Deal objectives; and minimizes water, land and chemical use.
In HALO-TEX, solvent-free techniques will be used for the extraction of feedstocks to preserve the quality of plant-based fibres. Then, the obtained fibres will be fractioned into hemicellulose, cellulose and lignin under mild conditions prior to be converted into bio-based textile and cosmetic additives. Lignin-based nanoparticles and micro-fibrillated cellulose will be obtained for the further production of yarns using spinning technologies in order to maintain touch, feel and look of the textile products without compromising their mechanical properties. Finally, the dyeability of yarns will be explored as well as their recyclability.
References:
- Annals of Botany (2015). Plant salt tolerance: adaptations in halophytes. - Timothy J. Flowers, Timothy D. Colmer.
- Journal of Experimental Botany (2006). Use of wild relatives to improve salt tolerance in wheat. – Timothy D. Colmer, Timothy J. Flowers, Rana Munns.
- Zoologischer Anzeiger (2007). Phylogeography of halophytes from European coastal and inland habitats. - Kurt Weising, Helmut Freitag.
- Preslia (2023). Inventory of the halophytes inland central Europe. Daniel Díte, Róbert Suvada, Tibor Toth and Zuzana Díte.
- Environmental and Experimental Botany (2013). Halophytes as forages in saline landscapes: Interactions between plant genotype and environment change their feeding value to ruminants. - Haley C. Norman, David G. Masters, Edward G. Barrett-Lennard.
- Environmental and Experimental Botany (2013). Three halophytes for saline-water agriculture: An oilseed, a forage and grain crop. - Edward P. Glenn, Tekie Anday, Rahul Chaturvedi, Rafael Martinez-Garcia, Susana Pearlstein, Deserie Soliz, Stephen G. Nelson and Richard S. Felger.
- Critical Reviews in Food Science and Nutrition (2021). Halophytes as source of bioactive phenolic compounds and their potential applications. - Maria Lopes, Anna Sanches-Silva, Maria Castilho, Carlos Cavaleiro and Fernando Ramos.
- Critical Reviews in Biotechnology (2012). Medical halophytes: potent source of health promoting biomolecules with medical, nutraceutical and food applications.