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The Future of Footwear is Algae

For the maker of Triton Soles, the world’s first flip-flop created from algae, the future of shoes is, quite literally, green.

As the recipient of a $2 million grant from the U.S. Department of Energy (DOE), the group of biologists and chemists has been charged with developing new ways of transforming algae into renewable and biodegradable versions of the plastic polymers known as polyurethanes.

Stephen Mayfield, who directs the California Center for Algae Biotechnology at the University of California, San Diego, says the so-called bioeconomy,” which the DOE and others are sinking investment dollars in, can bolster economic growth and diminish fossil-fuel use.

“This grant is part of a significant new initiative by the Department of Energy and other agencies to support the bioeconomy, which is using living organisms to manufacture products,” he said in a statement. “This is one of the fastest-growing sectors for creating new jobs, as well as for developing new advanced materials and products.”

Mayfield, fellow professors Skip Pomeroy and Michael Burkhart and their students found early success with algae-based polyurethane when they created what was hailed in 2015 as the “world’s most sustainable surfboard.” 

A few years later, they used algae oil to produce a flexible yet durable flip-flop with a triton-embossed sole and a simple strap.

As the No. 1 shoe in Africa, China and India, the flip-flop made for an obvious target. Roughly 3 billion new pairs of petroleum-based flip-flops are produced globally every year, according to Mayfield. Most end up as non-biodegradable trash in landfills, rivers and oceans.

“One of the largest pollutants in the ocean is polyurethane from flip-flops and other shoes that have been washed or thrown into rivers and flow into the ocean,” he said. Triton Sole’s flip-flops, on the other hand, are completely biodegradable and will degrade in a compost pile in about three months, Mayfield claimed.

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Though polyurethanes are key components in other types of footwear, including sneakers, the DOE grant will fund the development of more than recreational gear and shoes. The general idea is to crank out cost-effective plastics that are more ecologically friendly, no matter their utility. 

That’s not to say surfboards and flip-flops don’t make good gateway products, however. 

“Our strategy is to go from renewable algae feedstocks all the way to products that people actually want to buy,” Burkart said. “The surfboards were a big success, and we are excited to see how people like the flip-flops. Our goal is to get to 100 percent renewability and biodegradability. I believe that we can make an impact.”

As a whole, the plastics industry is ripe for disruption, and now is as good a time as any, added Pomeroy. 

“Originally founded on petroleum, [plastic has] to be redesigned because 1) the oil will run out and 2) because of their persistence in the environment as evidenced by the plastic trash heap in the middle of the Pacific Ocean,” he said.

Mayfield and his team aren’t the only ones spinning algae into footwear, either.

In 2017, London’s Vivobarefoot and Bloom, a materials innovation firm from San Diego, debuted the world’s first molded shoe derived from algae, which they turned into the closed-cell foam known as ethylene-vinyl acetate, or EVA for short.