Why did you decide to focus on seaweed drying?
One of the main bottlenecks in seaweed production is the post-harvest phase. Seaweed really degrades in a short amount of time, so if you don’t stabilize the seaweed in the first 24 to 48 hours, it loses a lot of value. We identified drying as the process with the best trade-off between shelf-life and bioactive compounds preservation.
After doing an extensive literature research and talking to different stakeholders we understood that today’s drying techniques leave a lot to be desired. The current methods are either complex and energy-consuming, like oven drying or freeze drying, or rudimental and uncontrolled, like line drying in big barns.
So with this in mind, we decided to design our own seaweed dryer, one that would be more energy efficient and user-friendly.
How does the Drylgae system work?
Our dryer relies on solar energy, so it reduces the energy inputs. It embeds a bio-inspired passive structure to dehumidify the seaweed. And finally we aim for an equipment that is light and resilient in order for it to be easily deployed as close as possible to the harvesting site, because of course it’s a major hurdle to transport your raw seaweed from your harvesting point to your drying facilities.
Can you explain the biomimetic principles at work?
We have three main modules. Two are dedicated to dehumidifying the air, the last one is dedicated to heating the air. The first structure is inspired by camel nostrils. To retain as much water as possible, camel nasal cavities have evolved in a way that dries the air very efficiently, basically by maximally increasing the contact surface.
The second module is a microporous membrane that is inspired by the Hercules beetle’s cuticle (the exoskeleton, red.). This insect’s cuticle basically absorbs water like silica gel – you have probably seen little bags of silica gel before, they come in anything from packaged foods to new shoes to keep moisture out.
Instead of silica we would absorb the remaining water in the air with a network of chitin filaments, which is the insect protein that the beetle’s cuticle is made of.
So at this point, we would have dried the engine’s air. But it still needs to be warmed up before entering the drying chamber. And this is where the last bio-inspired module comes in. This one is inspired by moth eyes. Moths avoid detection by predators through an anti-reflective coating on their eyes; this idea has already been used in some smartphone screens and other interfaces that need low reflection.
What we aim for here is that even with the slightest amount of light we are able to generate enough heat to warm up the air to around 35-40 degrees before it enters the drying chamber through this anti-reflective coating that maximizes the solar radiation absorption and thus maximizes solar heating.
What is the next step for Seastem?
Seastem reached the top 10 of the 2021 Biomimicry Global Design Challenge with our seaweed dryer concept. As a result, we are currently enrolled in the Launchpad organized by the Biomimicry Institute for ten weeks, which has allowed us to do extensive market research and validate our concept.
As of yet Drylgae is still a visual prototype and we have to confirm our technical expectations. In the next month we will start prototyping and join local and international consortia, begin the quest for funding and start growing our startup little by little.