As revolutionary as plastics were for changing the course of manufacturing forever, it’s become a major burden on the world. With 91% of plastics not being recycled and each of us consuming 5 grams of micro plastic every single week, there has to be a better solution. In a previous video I covered how fungus may be a viable plastic replacement for the future, but there’s another solution starting to bloom … Algae. And it’s showing up in a place you might not expect … your feet. What if I told you we could wear plastic-free flip flops made from algae?

Algae: A sea of opportunities

Algae seems to be proliferating in a number of fields from biofuels production to carbon capture.1,2 But the algal tide is tiptoeing towards a new fashion trend … sustainable footwear. Flip flops are endemic and contain non-recyclable plastic. Their production fuels climate change and ocean pollution, but we could soon be wearing plastic-free flip flops made from algae.3

Let’s start from the … roots … broadly speaking, algae are aquatic organisms that perform photosynthesis. Unlike land plants, their structure is much simpler. For instance, they have no roots, stem or leaves in some cases. You can find them both in freshwater, typically lakes, and seawater.4 Based on their size, you can distinguish between microalgae or phytoplankton, and macroalgae, a.k.a. seaweed, like the giant kelp.5

But what’s so special about algae? Their secret lies in their oily content which can perform as well as petroleum oil. Over the last two decades researchers have been exploring the potential of algae as a sustainable feedstock for making biofuels. They focused on extracting the algae oil-containing components to replace petroleum-derived oil. However, to upscale the technology, you’d need a massive amount of resources. It would take 50% of the yearly fertilizers used in European crop production to meet 10% of European transport fuel demand.

That’s why biotech startups are now diving into a new ocean of applications offered by this marine plant. Like C-combinator.6 Tackling the Sargassum algal blooms in the Caribbean sea, the Puerto Rico-based company is harvesting the surplus toxic algae to make useful products. Their extraction process upcycles this type of brown seaweed into more sustainable alternatives for agricultural, cosmetic, and textiles industries. The fashion world is one of the main drivers of plastic pollution. 35% of all microplastics that flush into the ocean comes from washing our synthetic clothing.7 Believe it or not, polyester is in 60% of what we wear.8 Sounds crazy? Just check the labels on your T-shirts and you’ll see.

Polyester is a petroleum-derived fiber, in other words plastic! It takes over 200 years to decompose and its global demand drinks up about 70 million barrels of oil each year.9 What about our shoes? Polyester is one of the staple textiles in our footwear design.10 On average, shoe production releases 450 billion pounds of CO2 every year.11 With a very low price, flip flops became the world’s best selling shoe, so you can see why these sandals are responsible for a massive share of shoes’carbon…foot…print.

On top of that, flip flops are typically made from an ethylene-vinyl acetate (EVA)-based foam. While EVA may be recycled, many flip flops contain non-recyclable polymers like PVC and polyurethane.12 That means they’ll be kicking around in a landfill for a hundred years, like in Ethiopia, which is one of the top consumers of flip flops.13 From there, they…walk…their way to the ocean. According to the conservation and recycling group Ocean Sole, ca. 90 tons of flip flops are discarded each year along the beaches of East Africa alone.14 Last year some researchers picked up 25 tons of trash along the beaches of the Aldabra, the world’s second-largest coral atoll, just off the East African coast. Around a quarter of that trash was flip flops.15

So, can we use algae to wipe away the plastic stains out of our footwear? Looks like we can. The Munjoi16 startup designed All-Dai, a 4-in-1 pair of shoes entirely made of plants. Playing around with this flexible footwear, you can shape it into four different types of shoes. Sneakers during the day, a slide or mule at night, or a sandal on the beach. Cool, right? But the interesting thing is that the bottom of the world’s most versatile shoes is made of BLOOM foam. It’s a mix of algae waste and sugarcane, as an alternative to the traditional petroleum-based EVA foam.

Flipping the script on plastic footwear

So, why algae? Besides growing 10 times faster than terrestrial plants, algae cultivation requires less than 10% of the land.17 Also, algae consume less water than land crops.18 Researchers from the University of California are growing microalgae in man-made ponds. Once fully developed, they separate the plants from water to obtain a sort of green…pesto…I mean…paste. They then extract the oily fraction out of the paste and turn it into a bio-foam to make flip flops.19

But how does that work? Using a machine in their lab, they pour the slimy green oil onto a mold. By applying heat, the algae oil is baked into a vegan cake … a solid foam which takes the shape of the flip flops components, including the footbed and the outsole. After about ten minutes, you open the mold, peel the pieces out and put them together to create a renewable sandal. With a bio-content of 52%, this eco-friendly beachwear fully biodegrades within 6 months in a compost pile. And even if they end up in the ocean, the algae-based flip flops will disappear in a year.20 That’s way quicker than petroleum oil-based footwear!

But can this be upscaled or is it just a flop? On the heel of their studies, the scientist group founded the Algenesis Materials startup to give it a go. The company is working with a number of footwear brands to launch their soft foams on the market. As mentioned on their website, REEF will be their first official partner for the commercial manufacturing of their flip flops. This should happen within a year or so.21 Algenesis’ Soleic™ technology could massively reduce the climate change impact of the shoes’ industry. Not only do fossil fuels stay in the ground, but algae also capture CO2 while growing.

Sounds great, right? But Algenesis has an Achilles heel. At the moment, they can’t buy enough algae to support their production. Algenesis’ founder believes the supply will grow as more algae farmers enter the market. And this may happen soon thanks to the support of the US Department of Agriculture. The 2018 Farm Bill gave farmers resources to put in place newer and more efficient ways of harvesting algal biomass.22

But Algenesis isn’t the only one to work on algae-based footwear. Back in 2016, the US-based company Bloom created the world’s first algae-blended EVA on the market, which should sound familiar … it’s the same foam used by the Munjoi shoe transformer I mentioned earlier. With a renewable content of at least 45%, their Bloom Foam, now known as Rise23, replaced shoes’ plastic soles. Partnering with the London-based Vivobarefoot brand, they made a splash with the launch of the Ultra III water shoe. Unlike Algenesis, Bloom doesn’t farm their algae in-house as they repurpose them from waterways affected by algal excessive proliferation like the Mississippi river.24

Deforestation, intensive agriculture and wastewater treatment are feeding our water bodies with a nutrient banquet perfect for algae to feast on and bloom wildly. This leads to harmful consequences25 such as oxygen depletion and sunlight blocking, which causes the death of wildlife as well as potential drinking water pollution.

Bloom embarked on an eco-crusade around the world. These…good pirates…are after a green treasure. Not dollars, just algae. Along the line of what C-Combinator does, their work is flipping a problem into a solution. The NorWegian company, Dynaspace, has developed a machine learning algorithm that could detect algal blooms through satellite imagery.26 But how does Bloom’s machine work? It’s got a giant vacuum that sucks up algae while a screen prevents fish and wildlife from getting caught. They then skim off the water from the plants through a continuous solar drying process. This system filters 175 gallons of algae-polluted water per minute, for a total recovery of 300 pounds of plants in a day.27 While recirculating the filtered water back into the environment, the dried algae are first pulverized and then made into pellets. These are injected into a mold to create a bio-foam. For each pair of Ultra III sneakers, Bloom cleans up 57 gallons of water and saves 40 balloons worth of CO2.28 …that’s what I call a climate-friendly party…Bloom’s algae-enriched EVA foam was used to design the Native Shoes’ sneakers in 2019.29 The Canadian brand touts to be the first and only to incorporate this material in the whole footwear design, including upper, midsole and outsole. Also, through their Remix Project, you can recycle their shoes. They regrind the footwear materials and repurpose them for seating, playground flooring, and insulation.

While still not entirely bio-based, algae are slowly sneaking into sneakers and flip flops. So, how do algae-based shoes stack up in terms of cost compared to traditional footwear? Algenesis touted a projected cost of $3 per pair, which would be comparable to other commercial flip flops.30 As for Bloom shoes, the rough estimate is that their cost is still slightly higher than 100% EVA footwear.31 But this is expected to drop as the process gets more efficient. Apparently Bloom created 100% biodegradable foams with a high algae content in the lab. But their viability is miles away from mass market adoption as of today.32 The main burden anchoring the algae shoes to the lab bench seems to be the raw material production.

Based on a comprehensive study published last year, we still need further development to make microalgae-derived bioplastic manufacture competitive at a commercial scale.33 On the other hand, some cash flow should sink the algae costs down as technology will improve over the years. For instance, in 2020 the U.S. Department of Energy invested a total of $27 million in R&D projects to ditch plastic for good. And Algenesis received part of this fund to develop their algae-based bioplastic.34 But, is it really worth surfing the algal wave from an economic standpoint? Well, the market for algae products is expected to grow at a CAGR of 6.30% from 2020 to 2027, reaching a value of nearly $1 Billion. And the demand for bioplastic seems to be one of the drivers of this organic growth.35

Walking towards a sustainable footwear path

Algae has a chance to be the oil of the future. While biofuels are still far from a commercial application, the shoe industry seems to be a step ahead in harnessing the potential of this green material. Although the more eco-friendly foams are still not 100% algae-based, companies may be on the right path to completely kick plastic out of our footwear.


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  2. “Algal biofuels challenges and opportunities ….” 9 Apr. 2019 ↩︎
  3. “Flip-Flops Made From Plants And Algae Can Help … – YouTube.” 6 Feb. 2021 ↩︎
  4. “What Are Algae? | Live Science.” 4 Jun. 2016 ↩︎
  5. “Difference Between Macroalgae and Microalgae | Compare the ….” 9 Mar. 2020 ↩︎
  6. “C-Combinator – Seaweed for Carbon Drawdown & Ocean Restoration.” ↩︎
  7. “Is fashion bad for the environment? | World Economic Forum.” 31 Jan. 2020 ↩︎
  8. “FAST FASHION, FATAL FIBRES – Greenpeace.” ↩︎
  9. “Making Climate Change Fashionable – The Garment Industry Takes ….” 3 Dec. 2015 ↩︎
  10. “Top 5 Most Common Materials Used to Make Shoes – Kicks Guide.” 30 Sept. 2017 ↩︎
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  12. “Eco Etiquette: How Can I Recycle Flip-Flops? | HuffPost.” ↩︎
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  14. “Flip Flop Facts: Find Out – Blue Ocean Network.” ↩︎
  15. “Flip-Flops Made From Plants And Algae Can Help … – YouTube.” 6 Feb. 2021 ↩︎
  16. “The All-Dai Shoe – Munjoi.” ↩︎
  17. “See How Algae Could Change Our World – Forbes.” 15 Jun. 2018 ↩︎
  18. “Alga – an overview | ScienceDirect Topics.” ↩︎
  19. “Eco-friendly polyurethane foam created from microalgae ….” 13 May. 2020 ↩︎
  20. “New Science Behind Algae-based Flip-flops – UC San Diego News ….” 6 Aug. 2020 ↩︎
  21. “Algenesis Products.” ↩︎
  22. “Funding Opportunity for Algae from the US Department of Agriculture.” 29 Jul. 2019 ↩︎
  23. “RISE | BLOOM | TREAD WELL.” ↩︎
  24. “Biomass – Introducing Algae foam in Shoes – TEXTILE VALUE CHAIN.” ↩︎
  25. “What is a harmful algal bloom? | National Oceanic and Atmospheric ….” 27 Apr. 2016 ↩︎
  26. “Dynaspace – Advancing Aquaculture Transparency.” ↩︎
  27. “Bloom Foam: From Waste to Wellness | Official Native Shoes™ Store.” ↩︎
  28. “Blog – VivobarefootXbloom.” 1 May. 2018 ↩︎
  29. “Native Shoes creates trainers from single piece of algae-laced foam.” 24 Oct. 2019 ↩︎
  30. “Here’s How Much Your Flip Flops Really Cost – IUIGA.” 28 Feb. 2019 ↩︎
  31. “Bloom’s Mission to Turn Toxic Algae into Shoes | Outside Online.” 22 Jul. 2019 ↩︎
  32. “Q&A: Using Algae to Create Sustainable Footwear.” ↩︎
  33. “Bioplastic Production from Microalgae: A Review – MDPI.” 28 May. 2020 ↩︎
  34. “US Department of Energy announces $27M in … – Biofuels Digest.” ↩︎
  35. “Global Algae Market Size By Product, By Application, By Geography ….” ↩︎

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