Renewable energy researchers have been turning to seaweed as a source of biofuel, and while that’s bubbling up in the background, the COVID-19 crisis has brought renewed attention to the all-around sustainability aspect of harvesting renewable resources from the sea. With that in mind, let’s take a look at some new developments in the field of seaweed, aka macroalgae.
Seaweed For COVID-19 Treatment, Possibly
No. Do not run out and buy random seaweed to treat yourself for COVID-19 symptoms. However, new research from Rensselaer Polytechnic Institute in New York does indicate that an extract from seaweed could “substantially” outperform the current go-to COVID-19 treatment, remdesavir.
The paper is available online at the journal Cell Discovery under the title, “Sulfated polysaccharides effectively inhibit SARS-CoV-2 in vitro.“
That’s in vitro, not in people, meaning that the research is still in early stages. Nevertheless, it is promising. The Renneslaer team deploys a “decoy” approach that has worked on dengue, Zika, and Influenza A, among other viruses.
The decoy material distracts the virus from latching onto human cells, and locks the virus into a safe space where it can degrade harmlessly.
COVID-19 Treatment, Seaweed Edition
For those of you keeping score at home, the seaweed extract used in the study consists of several variations of the common anticoagulent heparin.
And this is where it gets interesting. Heparin has been manufactured for 100 years or so, but almost all of it has been derived from animals, not seaweed. Our friends over at the National Institutes of Health journal Molecules have the backstory.
“The purification of heparin from offal is an old industrial process for which commercial recipes date back to 1922,” they write. “Although chemical, chemoenzymatic, and biotechnological alternatives for this production method have been published in the academic literature, animal-tissue is still the sole source for commercial heparin production in industry.”
They were saying that back in 2017, but since then it seems that research on the seaweed alternative has picked up steam.
Cost is still an obstacle for commercial interest in seaweed-derived heparin. However, with an unprecedented pandemic well under way and no end in sight, demand for COVID-19 treatments could help jumpstart the seaweed-to-heparin supply chain globally.
The renewable energy angle comes in because the seaweed-to-biofuel supply chain has also attracted little interest on a commercial level. If the heparin market spurs investor interest in seaweed farming for medical applications, economies of scale could also kick in and help bring down costs on the biofuel side as well.
Renewable Energy From The Sea, Heparin Industry Edition
The big question is why the heparin industry needs an alternative to offal. After all, the world is awash in offal. It’s cheap, it’s available, and something must be done with it.
Part of the answer could lie in mad cow disease, which sparked new restrictions on the re-use of offal. Consolidation in the rendering industry is also raising concerns about supply chains and price volatility. Over the long term, offal supplies could shrink as global demand for red meat fades (most pharmaceutical heparin is derived from cattle lungs and pig intestines).
More to the point, seaweed-derived heparin-type drugs could be more efficient than conventional heparin, as suggested by a 2019 study.
Kickstarting The Renewable Energy Market, Seaweed Edition
If all of that falls into place and COVID-19 helps stimulate commercial seaweed farming beyond its current scale, the implications for biofuel could be significant.
The US Department of Energy began prepping for such a venture in 2017, when it launched a new round of funding for the MARINER (Macroalgae Research Inspiring Novel Energy Resources) initiative, which aims to propel seaweed farming into the 21st century and deploy it as a renewable energy resource.
MARINER comes under the Energy Department’s cutting edge ARPA-E office, which specializes in high risk, high reward research.
Of particular interest is a project that involves ramping up farming methods for the brown seaweed Sargassum, which has also been studied for heparin extraction.
That project comes from the University of Mississippi, which received $500,000 in funding to create a system of semi-autonomous, wave powered tugboats that will reposition “paddocks” of Sargassum for optimum nutrient intake.
Renewable Energy From Seaweed & The Sustainability Twofer
The amount of time, energy, and expense involved in processing Sargassum for biofuel and other products is still problematic, partly because it involves drying as an initial step.
However, researchers have been working on that angle.
Last May, for example, the UK’s University of Exeter and University of Bath proposed a seaweed pretreatment method that tackles the problem. Here’s the explainer from Exeter:
“Using acidic and basic catalysts, the team devised a process that releases sugars that can be used to feed a yeast that produces a palm oil substitute. The same method also prepares the residual seaweed for the next stage of processing, called hydrothermal liquefaction.
“This process subjects the organic material to high temperature and pressure, turning the seaweed into bio-oil that can be processed further into fuels, and high-quality, low-cost fertiliser.”
Red carbon flags would normally go up at the mention of high temperature and pressure, except that nowadays low cost renewable energy is available to do the heavy lifting.
In addition, the Exeter/Bath solution indicates that the Sargassum-to-biofuel supply chain doesn’t necessarily have to rely exclusively on organized macroalgae farming. Invasive mats of Sargassum routinely clog beaches and impact the tourism industry in parts of the world. They are also linked to dead zones in the ocean. A biofuel pathway would help offset the costs of cleanup and improve both the environment and local economies, so there’s your sustainability twofer.
Of interest, the Bath/Exeter system is also designed to handle the plastic debris often intertwined with Sargassum mats, so there’s that.
Another angle that pops up is the potential for combining offshore wind farms with seaweed farming. Last week our friends over at Wind Power Monthly took note of an EU-backed North Sea seaweed project that aims at demonstrating multi-use benefits of cultivating seaweed for renewable energy at a 44-turbine offshore wind farm.
The new EU-backed “Wier & Wind” consortium is a partnership between Seaweed Harvest Nordsea, Murre Technologies, AtSeaNova and surveying firm GEOxyz.
If all goes according to plan, the North Sea project could provide a model for scaling up seaweed production elsewhere around the globe, with a consequent impact on the biofuel market in addition to other products including, possibly, pharmaceuticals for COVID-19 treatment.