Recovering more value from kelp: what a two-phase solvent study suggests
Naser Arda · Seaweed Economy
Recovering several useful products from the same kelp feedstock is an appealing prospect for seaweed processors. A new study offers a processing insight worth following: a solvent system may help make compounds accessible for recovery in a later step. The kelp studied, sugar kelp, is the kelp most farmed in BC, so the question is directly relevant to growers and processors here.
What the researchers tested
The study used Saccharina latissima, or sugar kelp. Researchers combined a fatty-acid phase targeting fucoxanthin with a betaine and urea phase targeting alginate, alongside citric-acid pretreatment for fucoidan and mannitol. Fucoxanthin is the pigment that gives brown seaweeds such as kelp their colour. It is used as an ingredient in supplements and cosmetics.
What they observed
Fucoxanthin recovery in the fatty-acid phase was limited: 41 to 58 micrograms per gram. A subsequent alkaline extraction step yielded 563 ± 8 micrograms per gram. These figures describe different stages; they are not a simple measure of improvement over conventional processing.
The authors interpret the results as suggesting that the system increased biomass permeability. Chromatographic profiles also suggested better fucoxanthin preservation than conventional extraction. These are proposed explanations supported by the observations, rather than confirmation of every underlying mechanism.
Why this could matter for processors
Seaweed Economy's interpretation is that the useful commercial question concerns the whole processing sequence. A processor would need to assess whether pretreatment improves the combined value of saleable products enough to justify the additional equipment, inputs and separation work.
For a business built around alginate, an additional pigment stream could be attractive if recovery is reliable and buyers accept its purity and specifications. Recovering a compound in an experiment does not establish a market-ready ingredient or profitable product stream.
The practical questions include:
- Does the sequence preserve the quality and functionality required for each target product?
- What separation and purification steps would buyers require?
- How much solvent can be recovered and reused, and at what cost?
- Do additional product revenues outweigh processing, quality-assurance and waste-management costs?
- How does performance vary across feedstock batches and operating conditions?
What remains unresolved
The authors recommend further work on solvent recyclability, techno-economic feasibility, life-cycle assessment and fuller characterisation of the extracted compounds. The study therefore does not establish a cheaper, lower-energy or environmentally superior commercial process.
What to follow next
For operators, this is a research direction to monitor when considering multiple product streams. For funders, a useful next milestone would be evidence connecting repeatable recovery, buyer-relevant product quality and credible process economics.
The question is whether pretreatment and subsequent recovery can work together in a process that delivers sufficient value at an acceptable cost and environmental impact.
Discussion question
What evidence would you need before adding a new recovery step to a seaweed processing operation?
The study by Hiemstra, Reynaga-Navarro, Wijffels, Eppink and Kazbar (Wageningen University, Nord University and TU Delft) was published open access on 25 September 2026 and funded by the Dutch Research Council (NWO) through the SeaSolv project. To explore how several products from the same biomass change the numbers, try the Extraction Economics Calculator in the Economics Lab.