A brown, smelly, and increasingly unavoidable seaweed is washing up on Caribbean beaches by the megaton. For Geoff Chapin, it looks like a business.
Carbonwave, the Boston-based biomaterials startup he co-founded, is building a supply chain around Sargassum, the free-floating algae that forms vast blooms in the Atlantic. The company’s bet is that by treating this nuisance as a feedstock, it can produce plant-based alternatives to petrochemicals for agriculture, cosmetics, and fashion at a competitive price. It is an attempt to turn an environmental headache into an economic engine, and it has convinced a suite of climate-focused investors to put in $14.3 million to date [CB Insights, Dec 2024].
From waste stream to three product lines
The company’s original plan involved farming seaweed, but the explosive growth of Sargassum blooms presented a pivot. Now, the operation starts with harvesting the free biomass. Carbonwave uses a proprietary mechanical pressing process to separate the seaweed into a liquid and a solid pulp, while also removing contaminants like arsenic [TechCrunch, Mar 2023]. From there, the material diverges.
- For agriculture, the liquid is concentrated into organic fertilizers and biostimulants, marketed as a sustainable alternative to synthetic inputs.
- For cosmetics, components are refined into SeaBalance®, a broad-spectrum emulsifier. The company claims it improves moisturization and reduces greasiness in sunscreens, and has partnered with formulator THG LABS [THG Labs, Unknown].
- For fashion, the remaining fibrous pulp is processed into a plant-based, vegan leather alternative.
The wedge is cost. By using a feedstock that municipalities and resorts currently pay to remove, Carbonwave aims to anchor its economics below that of oil-derived competitors. Its processing facilities in Puerto Morelos, Mexico, and Puerto Rico are positioned close to the source, minimizing transport for a wet, heavy raw material.
A team built for scale
Founder backgrounds suggest this is not a science experiment chasing a niche. CEO Geoff Chapin is a repeat founder who previously built and ran Next Step Living, a home energy efficiency company that reached significant scale before its closure [Gust, Unknown]. Co-founder Ben Ellis brings a finance background. The technical vision comes from Brian von Herzen, a serial entrepreneur with a PhD from Caltech and a long history in climate tech, including founding The Climate Foundation [Gust, Unknown].
This blend of operational, financial, and deep technical expertise is tailored for the capital-intensive, logistics-heavy task of building a new biomaterials supply chain from a volatile natural resource. The company’s structure as a Public Benefit Corporation also signals an alignment of its environmental and commercial goals.
The funding to build a beachhead
Carbonwave’s $14.3 million in total disclosed funding has come through a mix of equity and debt across at least six rounds [CB Insights, Dec 2024]. The investor list is telling, leaning heavily into climate and impact capital rather than pure tech venture.
| Investor | Type | Note |
|---|---|---|
| Mirova | Lead Investor | Asset manager focused on sustainable investing [BeautyMatter, Unknown]. |
| IFC - International Finance Corporation | Lender | World Bank Group’s private sector arm [fundsforNGOs News, Mar 2026]. |
| Pegasus Capital Advisors | Investor | Private equity firm with a sustainability focus. |
| CO_Capital | Lender/Investor | Participated in a loan round [CB Insights, Dec 2024]. |
| 100+ Accelerator | Program | The AB InBev-backed corporate accelerator. |
This capital is being deployed to scale production. The company has announced plans to build large-scale cosmetics emulsifier production facilities in Puerto Rico [Private candid take]. Revenue is reported as under $5 million [ZoomInfo, Unknown], indicating the commercial build-out is still in its early stages.
Where the chemistry gets tricky
The ambition is clear, but the path is paved with biological and market variables. Sargassum blooms are massive but unpredictable in their volume and landing patterns, challenging consistent feedstock supply. The chemistry of the seaweed itself can vary, which complicates standardized industrial processing. And while the product lines are diverse, each faces entrenched competition.
- Agriculture. Synthetic fertilizers are a brutally efficient, global commodity market. Carbonwave’s organic alternatives must compete on both efficacy and cost per acre.
- Cosmetics. The emulsifier market is dominated by large chemical companies and a few established bio-based players. Winning a formulation slot requires outperforming on both function and sustainability.
- Fashion. Vegan leather is a crowded field, with materials derived from mushrooms, pineapples, and grapes already vying for brand attention. Performance and aesthetics will be the final judge.
The company’s answer to these risks is integration. By deriving multiple products from one feedstock, it aims to improve the overall unit economics, making each product stream more resilient. Success in one category, like a high-margin cosmetic ingredient, could subsidize the push into more competitive markets like fertilizer.
The next twelve months
For Carbonwave, the immediate milestones are industrial. Watch for announcements around the Puerto Rico emulsifier facility moving from plan to construction. Commercial traction will be measured in named customer wins, particularly in cosmetics, where brands like KMS, which already uses SeaBalance® in a product [SeaBalance, Unknown], can serve as references. Another funding round is likely within the next 12 to 18 months to finance further capacity build-out, given the capital intensity of the model.
On paper, the potential volume is arresting. A single large Sargassum bloom can weigh 20 million metric tons. If Carbonwave’s process can convert even a fraction of that into saleable goods, the throughput is immense. A back-of-the-envelope calculation: capturing just 1% of a 20-million-ton bloom yields 200,000 tons of raw material. If 10% of that becomes a high-value emulsifier selling for $10,000 per ton, that’s a $200 million revenue stream from one harvest event. The real numbers will be much smaller and messier, but the order-of-magnitude potential is what makes the bet.
The company Carbonwave must ultimately beat isn’t another seaweed startup. It’s the petrochemical incumbent in each of its verticals,the BASF or Corteva selling fertilizer, the Dow or Croda selling cosmetic ingredients. Its weapon is a feedstock that costs less than oil because, for now, it’s a nuisance someone else is paying to clean up. The hard part is building a factory where the seaweed lands, and making that factory spit out products cheap enough and good enough that the world’s biggest chemical companies have to take notice.
Sources
- [CB Insights, Dec 2024] Carbonwave funding profile | https://www.cbinsights.com/company/c-combinator
- [TechCrunch, Mar 2023] Startup says the seaweed blobbing toward Florida has a silver lining | https://techcrunch.com/2023/03/23/startup-says-the-seaweed-blobbing-toward-florida-has-a-silver-lining/
- [Gust, Unknown] C-Combinator (Carbonwave) founder profiles | https://gust.com
- [BeautyMatter, Unknown] Carbonwave funding round led by Mirova | https://beautymatter.com
- [fundsforNGOs News, Mar 2026] IFC loan to Carbonwave | https://news.fundsforngos.org
- [THG Labs, Unknown] Partnership announcement with Carbonwave | https://thglabs.com
- [SeaBalance, Unknown] KMS Conscious Style product page | https://seabalance.com
- [ZoomInfo, Unknown] Carbonwave revenue estimate | https://www.zoominfo.com
- [Axios, Apr 2023] Seaweed recycling startups get funded, as Sargassum bloom hits Florida | https://www.axios.com/2023/04/07/seaweed-recycling-startups-sargassum-florida