What if the plants we once overlooked along our coasts could help reshape the future of sustainable industry? From forgotten “sea herbs” to pioneers of circular innovation, halophytes are emerging as powerful allies in the transition toward a more resilient and bio-based world.
For centuries, these salt-tolerant plants, growing in saline or marginal lands, were part of everyday life, harvested for food, seasoning, and traditional remedies. Today, we walk past them without noticing, yet their potential has never been greater. Growing where few other crops can survive, halophytes, often called sea herbs, are now being rediscovered as valuable resources for sustainable textiles, bioactive cosmetics, and circular biorefineries. In a world facing soil salinization, freshwater scarcity, and climate change, these resilient plants may hold keys to both ecological restoration and innovative bio-based industries.
Where Land Meets Sea
Before laboratories and life-cycle assessments, before the language of bioeconomy and circularity, people knew these plants by touch and taste.
These plants live where land meets the sea: in mangroves, marshes, swamps, and along beaches, resilient to high salinity and extreme conditions.
As Jakob Lykke Stein, researcher at HALOREFINE in the HALO-TEX project, explains, a hundred years ago in Denmark, coastal communities were familiar with succulent salt-tolerant plants (halophytes) growing along the shore. Some of these plants were harvested and added fresh to meals, valued for their naturally saline taste and crisp texture. Before industrial salt production became widespread, salt was commonly obtained through processes such as evaporating seawater, which could be laborious and energy-intensive. Coastal herbs, however, offered a distinctive flavour that complemented local diets.
These “sea herbs” were sometimes eaten fresh in salads, while others could be dried or further prepared. Some also appeared in traditional practices long before modern science began identifying their chemical properties.
Halophytes are not new plants. They are coastal species we once stepped on, harvested and ate, and gradually forgot as agriculture industrialised and supply chains globalised.
Today, we are rediscovering them. Not out of nostalgia, but out of necessity.
Why Salinity Is Becoming a Challenge
Climate change is reshaping agriculture. Hotter summers, prolonged droughts and irregular rainfall patterns are exacerbating soil salinisation in many regions worldwide. When irrigation water evaporates, dissolved salt remains in the soil. Over time, particularly under conditions of poor drainage and high evaporation, salt can accumulate to levels that severely limit or prevent the growth of conventional crops.
“In a lot of places already now, we cannot grow our traditional crops,” explains Mette Hedegaard Thomsen, professor at Aalborg University, in the HALO-TEX project. “So, we need to look at these types of plants that can grow in these salinized soils.”
Halophytes can grow where most crops fail. They evolved in saline environments and developed mechanisms to tolerate and regulate salt. But they do more than survive.
When cultivated on degraded saline soils, halophytes absorb salt into their biomass. Once harvested, part of that salt is removed from the system. This makes them potential tools for soil remediation and crop rotation strategies in affected areas.
They are not just alternative crops. They are part of a regenerative solution.
More Than Resilient: A Molecular Resource
“Halophytes are old medicinal plants,” Mette explains. “They contain a lot of very bioactive compounds called polyphenols.” Growing in what she describes as a toxic environment, the plants produce active substances, antioxidants and anti-inflammatory compounds, which are now being explored for cosmetic formulations and textile applications.
But their value does not stop at these bioactive components. Halophytes also provide structural material. Their stems and fibers can be processed to extract cellulose for textile production, while the woody fractions contain lignin that can be used in surface treatments with flame-retardant and water-repellent properties.
In the HALO-TEX project, halophytes are treated as a complete biorefinery feedstock, with every part of the plant used through a cascade process:
- Extraction of bioactive compounds: Polyphenols and other valuable substances are removed first for cosmetic use and as antioxidants in textiles.
- Removal of hemicellulose sugars: The plants contain both hemicellulose and cellulose, and the sugars from hemicellulose can also be valorized in cosmetic products.
- Separation of cellulose and lignin: The remaining structural fractions are separated. Cellulose is processed into textile fibers, while lignin is applied in textile surface treatments.
This cascading approach ensures that the full potential of the plant is used, combining material production with high-value bioactive applications.
Why These Two Species?
Within HALO-TEX, two halophyte species were selected for specific reasons.
Sea Aster, the pink-flowered plant commonly seen along European coastlines, was chosen because it is highly fibrous. This makes it promising for cellulose extraction and lignin recovery. Harvesting is timed after flowering, allowing pollinators to benefit first, contributing to biodiversity.
Salicornia perennis is a long-living halophyte that develops stronger, more woody stems than many annual succulent species, making it ideal for cellulose and lignin extraction.
Gijs van Erven, researcher at Wageningen University & Research, in the HALO-TEX project, explains:
“Halophytes are obviously our plants. They are composed of different parts, stems, flowers, each with distinct constituents. The stems mainly contain cellulose and are woody. We are very interested in valorizing this woody biomass, separating lignin from the cellulosic fibers, and finding suitable applications for both the lignin and the fibers.”
Salicornia also produces abundant polyphenols, which are highly valued for cosmetic applications due to their documented antioxidant, anti-inflammatory and anti-aging effects. Together, the structural and molecular features of these species make them perfect candidates for HALO-TEX’s integrated biorefinery approach, combining environmental benefits with high-value outputs.
A New Feedstock for Sustainable Textiles
The textile industry is under pressure to reduce freshwater consumption, carbon emissions, and dependence on fossil-based materials. Cotton requires large amounts of water and fertile land, while synthetic fibers rely on petrochemicals.
“The textile industry needs new feedstock,” Mette explains. “They need more sustainably grown fibres for their production to be fully sustainable.”
Halophytes can grow on saline or degraded soils where conventional crops cannot. This reduces competition with food production and opens new agricultural models adapted to changing climate conditions.
In addition, the coastal wetlands where halophytes naturally grow are important carbon sinks. These ecosystems capture significant amounts of CO₂, making halophytes part of a broader environmental transition strategy. They do not solve everything, but they address multiple challenges at once.
Designing With What Was Already There
Halophytes are not futuristic inventions. They are ancient coastal companions.
What is new is the system built around them, connecting soil remediation, molecular extraction, cosmetic innovation and sustainable textile production into one integrated value chain.
We used to step on these plants on our way to the sea.
Now, facing salinised soils, water scarcity and the need to move beyond petrochemical dependency, we are learning to design with them carefully, systematically, and molecule by molecule.