The science behind OSU's seaweed project
Oregon State University’s patented dulse seaweed, for human consumption, can be traced to a project that dates back almost 20 years.
Professor Chris Langdon came to OSU in 1986 from the University of Delaware to work on oysters. Seaweed had not been part of his research until it he started examining examining it as feed for abalone about 20 years ago.
It was then that Langdon and his team of researchers looked at different strains of dulse seaweed (Palmaria mollis) — found from Alaska to mid-California.
A graduate student noticed that in one tank, a mutated strain of the dulse collected from Puget Sound, had a different shape. Its leaves were broader than the others and it grew much faster. The other samples that were gathered from San Luis Obispo didn't show the same growth rates and the leaves were much finer.
“It was an accidental discovery,” Langdon said. “It’s like a lot of plants, where there’s a natural mutation and they change their morphology.
“It’s naturally cloning; all of the plants are vegetatively growing,” he said. “The plants are dividing continually. We take the plant and pull it apart and each of these little pieces will grow into another plant that’s identical to the parent. That’s the beauty of this seaweed. It just grows forever. And once you’ve found a mutant that looks a little different, you can perpetuate that as well.”
Once the researchers had cloned enough of the C-3 variety, named for one of the tanks where the mutant was discovered, they created an experiment with abalone and developed the technology to grow the two together in a closed system.
“The seaweed turned out to be a good food for the abalone, and the abalone excretes ammonia and CO2 that’s absorbed by the plant, turned into protein and the abalone eats the plant. So there’s a cycle of nutrients between the abalone and dulse,” he said.
With the experiment a success, the technology was licensed to a company, Big Abalone Corp., started by a graduate student who worked on the project.
After the project ended, Langdon kept the C-3 specimens growing in tanks at OSU's Hatfield Marine Science Center. Those same specimens are now being used to create seaweed for human consumption.
Several 1,500-gallon tanks, seeded with offspring from those first specimens, are now supplying Dulcenergy, the Imperial restaurant in Portland, and OSU's Food Innovation Center with seaweed.
The tanks are housed under a clear greenhouse-like structure, with netting to shade them from the sunlight. Too much sun can cause the seaweed to be bleached and damaged. In nature, the seaweed likes to grow on the underside of rocks in the shade or on the north-facing surfaces away from the sun.
Wild seaweed anchors itself to rocks, Langdon said. But in the tanks, the seaweed floats freely, constantly being agitated by air pumped through the bottom of the tanks and a constant exchange of seawater.
To be able to commercialize production of the seaweed, Langdon and his graduate assistant, John Hulsey, have determined the ideal density of the plants in each tank.
A grant from the Oregon Department of Agriculture is now funding further study to determine whether the seaweed can be grown in a closed system. There are also no commercial operations that grow dulse for human consumption in the U.S., according to the Associated Press.
Scientists already have found the least amount of salinity that the seaweeds will withstand before they don’t thrive.
Several rows of smaller tanks are set up, each replicating an experiment where the volume of new seawater is lowered in each tank. The water exchange-rate in some tanks is once per week, others are once every two weeks and others are once every three weeks. In each row, there’s a control tank where the seawater is constantly being exchanged. Each tank is also fertilized with nutrients at varying intervals, with researchers intent on discovering how little fertilization is needed before the seaweed no longer thrives.
For companies to grow the seaweed inland, away from the shore, they’ll need the information that Langdon and Hulsey are collecting in order to minimize cost. Exchanging seawater, whether it's real seawater or artificial seawater like the kind used in aquariums, is expensive, Langdon said. And so are the nutrients for the seaweed. So the fewer nutrients and less water exchange required, the lower the cost. Scientists are also trying to determine how much light is ideal.
“The really important story about this seaweed is that it’s a sustainable source of protein and of micronutrients and antioxidants,” Langdon said.
"Thinking long-term, we’ve got to look at other ways of producing protein for human consumption that doesn’t rely on terrestrial sources of fresh water and land," he said. "Because, as we go forward, the globe is going to become more populated and, as we have global warming, there’s going to be less fresh water for the cultivation of crops.”
“If we can grow things in seawater that’s nutritious, we’ll have an endless supply of food,” he said.
Also, unlike most other forms of aquaculture, this doesn’t generate waste products. The dulse actually cleans the water by removing excess nutrients and CO2. “This project is very environmentally friendly and I think that’s a bigger part of the story,” Langdon said.
The scientists also discovered that dulse absorbs nutrients quickly, so there's a possibility to boost concentrations of certain micro nutrients such as iron or iodine. This would create customized dulse with higher levels of iron for people suffering from anemia or higher concentrations of iodine for people suffering from goiter, Langdon said.
There also is the potential to use dulse in a wide variety of products, including snack foods, and as an ingredient that provides meat flavor to vegetarian food.
“Some big food companies have been in touch with us,” Langdon said, “about using it as a meat substitute for vegan or vegetarian burgers.”
The potassium content of the dulse lends a salty flavor when used in foods That could lead to less sodium in savory food — something that may help with high blood pressure or heart disease.
Since news of OSU’s seaweed has spread, Langdon said he has been flooded with inquiries. “We’re obviously working with interested Oregon companies, but we’ve had inquiries from people all over the world including Korea, Israel and Africa,” he said.
Langdon said confidentiality agreements prevent him from disclosing names, but there are two dozen inquiries from companies seriously interested in growing dulse. Two of them have taken the next step and started working with an economist to develop business plans.
Not all of the companies are thinking about growing the seaweed inland either. Hulsey is working with one of the companies, based in California, to help it develop an offshore seaweed growing system.
Langdon said he hopes his work kicks off an examination of other varieties of sea plants for commercial application for human consumption: “I think there’s a huge potential here.”