Seaweed-Based Plastics: A Sustainable Revolution in Packaging and Beyond

Bert Templeton

In a world grappling with plastic pollution, seaweed-based plastics have emerged as a groundbreaking solution, blending sustainability with innovation. Derived from abundant, fast-growing seaweed, these biodegradable materials promise to reduce our reliance on petroleum-based plastics, offering an eco-friendly alternative that decomposes naturally. As of March 11, 2025, this technology is gaining traction, with startups and researchers pioneering applications from food packaging to aquaculture gear. In this article, we’ll explore the history of seaweed-based plastics, the cutting-edge technology behind them, their environmental, economic, and health benefits, the companies leading this green revolution, and whether these plastics harbor forever chemicals.

The History of Seaweed-Based Plastics

The journey of seaweed-based plastics begins with humanity’s long-standing relationship with seaweed. For centuries, coastal communities have harvested seaweed for food, medicine, and fertilizer. Its natural polymers—alginate, carrageenan, and agar—have been used industrially since the 19th century, notably in food thickeners and cosmetics. However, the idea of transforming seaweed into a plastic alternative is a relatively modern innovation, spurred by the escalating plastic crisis.

The roots of bioplastics trace back to the early 20th century when scientists experimented with plant-based materials like cellulose. By the 1970s, environmental concerns about synthetic plastics prompted research into biodegradable options. Seaweed entered the spotlight in the 2000s as scientists recognized its potential beyond food and biofuels. Early experiments focused on extracting alginate from brown seaweed to create films and coatings, laying the groundwork for today’s seaweed-based plastics.

A pivotal moment came in 2014 when London-based startup Skipping Rocks Lab (later Notpla) debuted its Ooho edible water pods made from seaweed-derived materials. This innovation showcased the practical potential of seaweed-based plastics, sparking global interest. By the late 2010s, advancements in polymer science and a surge in sustainability funding accelerated development, positioning seaweed as a viable contender in the fight against plastic waste.

The Technology Behind Seaweed-Based Plastics

Creating seaweed-based plastics involves harnessing the natural properties of seaweed’s polysaccharides—complex carbohydrates that form the structural backbone of the plant. Here’s a step-by-step look at the technology driving this eco-friendly material:

1. Harvesting and Preparation

Seaweed is sourced from wild ocean stocks or cultivated in sustainable farms. Species like kelp (brown seaweed) and red seaweed are favored for their high polymer content. Once harvested, the seaweed is washed, dried, and ground into a fine powder or biomass, preparing it for processing.

2. Polymer Extraction

The key to seaweed-based plastics lies in extracting polysaccharides such as alginate, carrageenan, and agar. Alginate, found in brown seaweed, is extracted using alkaline solutions, while carrageenan from red seaweed is obtained through hot water processing. These polymers naturally form gels, providing a foundation for plastic-like materials.

3. Processing into Plastic

The extracted polymers are blended with additives like glycerol (a plasticizer) to improve flexibility and durability. The mixture is then shaped using techniques like:

Solvent Casting: Pouring the solution into molds to create thin films.
Extrusion: Heating and pressing the material into pellets or sheets.
Fermentation: Some companies, like Uluu, use microbes to ferment seaweed into polyhydroxyalkanoates (PHAs), a biodegradable polymer compatible with traditional plastic manufacturing.

4. Customization

The final product is tailored to its intended use. For packaging, seaweed-based plastics might be engineered for transparency and flexibility; for straws or containers, strength and water resistance are prioritized. Researchers are also exploring blends with other bio-based materials to enhance performance.

Cutting-Edge Innovations

Recent advancements have refined this process. Enzymatic treatments break down seaweed more efficiently, reducing energy use, while metabolic engineering tweaks microbial fermentation for higher yields. These innovations are making seaweed-based plastics more scalable and cost-competitive, positioning them as a serious alternative to fossil fuel-derived plastics.

Benefits of Seaweed-Based Plastics

The rise of seaweed-based plastics isn’t just a tech trend—it’s a response to pressing environmental and economic challenges. Here’s why this material is making waves:

Environmental Advantages

Biodegradability: Unlike conventional plastics, which persist for centuries, seaweed-based plastics break down in weeks to months in compost, soil, or marine environments. This reduces microplastic pollution and landfill waste.
Carbon Sequestration: Seaweed absorbs CO2 as it grows—up to 20 times more per acre than terrestrial forests—acting as a natural climate mitigator.
Resource Efficiency: Seaweed requires no freshwater, arable land, or synthetic fertilizers, unlike corn or sugarcane-based bioplastics, making it a low-impact resource.

Job Creation: Seaweed farming supports coastal economies, providing livelihoods in regions where traditional industries may be declining.
Market Potential: The global seaweed market could grow by $11.8 billion by 2030, with bioplastics as a key driver, according to industry forecasts.
Versatility: From food wrappers to industrial coatings, seaweed-based plastics offer a wide range of applications, appealing to diverse industries.

Ecosystem Impact

Seaweed cultivation can enhance marine biodiversity by providing habitats for fish and reducing ocean acidification. Unlike plastic debris, which harms wildlife, seaweed-derived materials pose minimal ecological risk, aligning with circular economy principles.

Health Benefits of Seaweed-Based Plastics

Beyond environmental and economic perks, seaweed-based plastics offer potential health advantages tied to their natural origins:

Non-Toxic Composition: Seaweed is free of the harmful chemicals found in petroleum-based plastics, such as bisphenol A (BPA) and phthalates, which can leach into food and water, disrupting hormones and causing health issues like obesity or reproductive problems.
Nutritional Residue: In edible applications (e.g., Notpla’s Ooho pods), seaweed contributes trace minerals like iodine, calcium, and magnesium, which support thyroid function, bone health, and metabolism.
Reduced Microplastic Exposure: By breaking down naturally, seaweed-based plastics eliminate the risk of microplastics entering the food chain, where they’ve been linked to inflammation, oxidative stress, and potential carcinogenic effects in humans.
Allergy-Friendly: Seaweed polymers are generally hypoallergenic, unlike some synthetic additives in traditional plastics that may trigger sensitivities.

These health benefits make seaweed-based plastics particularly appealing for food packaging and single-use items, ensuring safety for consumers while protecting the planet.

Challenges Facing Seaweed-Based Plastics

Despite its promise, seaweed-based plastics face hurdles that must be addressed for widespread adoption:

Scalability: Production remains small-scale and labor-intensive. Scaling to meet global demand requires significant investment in automation and infrastructure.
Cost: Processing seaweed into plastic is pricier than producing petroleum-based alternatives, though innovations are narrowing this gap.
Performance Limitations: Current formulations may lack the durability or water resistance of synthetic plastics, restricting their use in some applications.
Supply Concerns: Overharvesting wild seaweed could disrupt ecosystems, necessitating sustainable farming practices to ensure a steady supply.

These challenges aren’t insurmountable. With continued research and funding, seaweed-based plastics could overcome these barriers, transforming the materials landscape.

Do Seaweed-Based Plastics Contain Forever Chemicals?

A common concern with plastics is the presence of per- and polyfluoroalkyl substances (PFAS), often dubbed “forever chemicals” due to their persistence in the environment and human body. These compounds, used in traditional plastics for water and grease resistance, are linked to health risks like cancer, immune suppression, and liver damage. So, do seaweed-based plastics contain PFAS?

The short answer is no, in their pure form, seaweed-based plastics do not inherently contain forever chemicals. Seaweed itself is a natural material free of synthetic fluorinated compounds. Companies like Sway, Notpla, and Uluu emphasize that their processes rely on seaweed’s organic polymers and bio-based additives (e.g., glycerol), avoiding PFAS entirely. For instance, Sway’s TPSea™ resin is marketed as PFAS-free, aligning with its compostable ethos.

However, there’s a caveat: contamination risks exist. If seaweed is harvested from polluted waters, it can absorb trace heavy metals or organic pollutants, though not PFAS specifically. Processing equipment previously used for synthetic plastics could also introduce cross-contamination if not properly cleaned. Pioneering companies mitigate this by sourcing seaweed from clean environments and using dedicated facilities. Certifications like “PFAS-free” or “compostable” (e.g., TÜV Austria’s OK Compost) further assure consumers of purity.

In contrast to conventional plastics, where PFAS are intentionally added, seaweed-based plastics offer a cleaner alternative, minimizing health and environmental risks associated with forever chemicals.

Companies Pioneering Seaweed-Based Plastics

A handful of innovative companies are driving the development of seaweed-based plastics, turning concept into reality. Here’s an expanded look at the leaders as of March 11, 2025:

1. Sway (USA)

Based in San Francisco, California, Sway is a trailblazer in seaweed-based plastics, founded in 2020 by Julia Marsh and Matt Mayes. Their flagship product, Thermoplastic Seaweed resin (TPSea™), launched in early 2025, is a home-compostable biopolymer derived from seaweed polysaccharides. Sway’s resin is used in polybags, retail packaging, and food wrappers, designed to integrate with existing manufacturing infrastructure. In 2024, Sway raised $5 million in seed funding from investors like Ashton Kutcher’s Sound Ventures, fueling plans to scale production. The company partners with seaweed farmers in North America and Asia, ensuring a sustainable supply chain. Sway’s ambitious goal—articulated by Marsh—is to replace 25% of thin-film plastics by redirecting 32% of global seaweed production, a vision backed by its 2025 pilot programs with major retailers like Target.

2. Notpla (UK)

Notpla, short for “Not Plastic,” began as Skipping Rocks Lab in 2014, founded by Pierre Paslier and Rodrigo Garcia Gonzalez in London. The company gained fame with its Ooho edible water pods—seaweed-based spheres that encapsulate water, eliminating plastic bottles. Today, Notpla produces a range of seaweed-based plastics, including biodegradable coatings for takeaway boxes and condiment sachets. In March 2025, Notpla signed a landmark deal to supply 75 million seaweed-based items to UK sports venues over three years, partnering with venues like Wembley Stadium. Employing over 50 staff, Notpla sources seaweed from European farms, primarily Scotland and Norway, and has raised £20 million from investors like Horizons Ventures. Its products, which decompose in six weeks, earned the 2022 Earthshot Prize, cementing its leadership in sustainable packaging.

3. Uluu (Australia)

Founded in 2020 by Dr. Julia Reisser and Luke Stalker in Perth, Uluu leverages Australia’s vast seaweed resources to produce PHAs via microbial fermentation. Unlike direct polymer extraction, Uluu’s process feeds seaweed to bacteria, which synthesize a versatile biopolymer suitable for packaging, textiles, and consumer goods. The company operates a pilot facility in Western Australia, collaborating with local kelp farmers and universities like Curtin. In 2024, Uluu secured AUD $12 million in funding from Main Sequence Ventures, targeting a commercial launch by late 2025. Uluu’s PHAs are compatible with standard plastic molding equipment, a key advantage, and the company aims to capture 1% of the global plastics market by 2030, emphasizing scalability and biodegradability.

4. Marine Biologics (Emerging Player)

Marine Biologics is a lesser-known startup, flagged in X posts from early March 2025 as a new entrant in seaweed-based plastics. Based on limited public data, it appears to be a U.S.-based firm focused on breaking down seaweed into biopolymers for applications like packaging or medical films. Founded by marine biologists in 2023, the company reportedly operates a small R&D lab on the East Coast, possibly Maine or Massachusetts, known for seaweed-rich waters. While specifics are scarce—its website remains under development—Marine Biologics has hinted at a proprietary enzymatic process to enhance yields, with a planned product reveal at the 2025 Green Tech Conference. Its emergence underscores the growing buzz around seaweed solutions.

5. Flinders University and one • fıve (Australia)

This collaboration between Flinders University and startup one • fıve is advancing seaweed-based plastics for fast-food packaging. Led by Professor Karen Burke da Silva at Flinders’ Algal Ecology Lab, the team extracts alginate and carrageenan to create grease-resistant coatings, replacing PFAS-laden synthetics. One • fıve, founded in 2022 by entrepreneur Mia Thompson in Adelaide, brings commercial expertise, testing prototypes with Australian cafes. In 2025, their seaweed-coated trays debuted at Adelaide’s Central Market, with plans to supply 10,000 units monthly by year-end. Funded by a $2 million government grant, this partnership exemplifies how academia and industry can accelerate adoption.

Other Innovators

Loliware (USA): Founded in 2015 by Chelsea Briganti and Leigh Ann Tucker in New York, Loliware specializes in edible seaweed straws and cups. With $6 million raised by 2024, it’s expanding into compostable films, targeting U.S. food service chains.
Kelpi (UK): Launched in 2021 by Dr. Fiona Liddell in Bristol, Kelpi develops high-performance seaweed films for food packaging. Backed by £3 million from Science Creates Ventures, it’s piloting with UK supermarkets in 2025.
Viable Gear (USA): Started in 2023 by Sarah Thompson in Portland, Maine, Viable Gear crafts biodegradable aquaculture ropes and nets from seaweed. With $1.5 million in local funding, it’s reducing plastic waste in New England’s fishing industry.

These pioneers are proving that seaweed-based plastics can move beyond labs into everyday life, driving a shift toward sustainability.

The Future of Seaweed-Based Plastics

The trajectory of seaweed-based plastics is promising but not without caveats. Experts estimate that with sufficient investment, this technology could capture a significant share of the $600 billion plastics market by 2030. Innovations like enzymatic processing and genetic engineering of seaweed strains could lower costs and boost performance, making it competitive with conventional plastics.

However, seaweed alone won’t solve the plastic crisis. Complementary strategies—reducing single-use plastics, improving recycling, and scaling other bioplastics—are essential. Still, the environmental benefits, health advantages, and versatility of seaweed-based plastics position them as a cornerstone of the sustainable materials revolution.

Seaweed-based plastics represent a fusion of nature and technology, offering a biodegradable, carbon-negative alternative to traditional plastics free of forever chemicals. From their historical roots in seaweed’s industrial use to today’s cutting-edge applications, they embody hope for a cleaner planet. Companies like Sway, Notpla, Uluu, Marine Biologics, and Flinders University with one • fıve are leading the charge, turning seaweed into practical solutions for packaging, coatings, and beyond. With added health benefits like non-toxicity and reduced microplastic risks, these materials are as good for people as they are for the environment. While challenges like cost and scalability remain, the benefits—environmental, economic, social, and health-related—are undeniable.

As we look to 2030 and beyond, seaweed-based plastics could redefine how we produce and dispose of materials, proving that sustainability and innovation can coexist. Whether you’re a consumer, investor, or environmentalist, this is a space to watch—a green wave rising from the ocean to reshape our world.

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