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Is Seaweed the Answer to Single-Use Plastic?

The company behind a seaweed-derived alternative to polybags and other forms of single-use plastic has closed on a $2.5 million seed raise led by a Starbucks-affiliated fund.

Sway, a Berkeley-based biomaterials firm, raised enough cash from Valor Siren Ventures, along with Alante Capital, the Sustainable Ocean Alliance and Conservation International Ventures, to start plotting some pilot projects next year, it said Thursday.

A winner of Target’s Beyond the Bag challenge in February, Sway seeks to make compostable packaging that “replenishes the social and ecological systems harmed by petroleum plastic.”

The apparel supply chain employs roughly 180 billion polybags made from low-density virgin polyethylene every year, according to innovation platform Fashion for Good. While the packaging serves a useful purpose—protecting garments from dirt, moisture damage and mold during transit—they’re also part of the escalating plastic crisis. Of the 86 million tons of plastic packaging produced globally every year, less than 14 percent is recycled. The rest is landfilled, incinerated or set loose on the environment, where they can clog waterways or poison wildlife.

Sway’s aquatic version, made from a “benevolent resource,” is designed to disappear—not immediately but in four to six weeks under backyard conditions. The filmy material “technically outperforms” petroleum plastic, the company said. “By matching the strength and performance of traditional plastic bags, the bag fits into existing supply chains without needing any new infrastructure,” it added.

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Seaweed also grows up to 60 times faster than land-based crops and can sequester up to 20 times more carbon dioxide per acre than forests, according to Sway. But the company doesn’t simply plunder oceans for the green stuff. Sway works regenerative seaweed farms, operated by coastal communities in Brazil, Chile and Mexico that have been impacted by overfishing and climate change, to cultivate its feedstock inexpensively and without pesticides, fertilizers or specialized equipment.

“While petroleum plastic contributes to climate change at every step of its lifecycle, Sway’s flexible packaging solution is made with process in mind,” Sway said. “We work to undo the harms of plastic pollution everywhere, from the ocean to your backyard. Rather than seeing the ocean only as a site of degradation, we believe an answer to our biggest climate challenges—on land and at sea—has been underwater all along.”

Polybags are a puzzle that the industry has been trying to crack, with various degrees of success. Companies have been experimenting with bags made from corn polymers or cassava root, reusable mailers composed of recycled billboards and enclosures derived from Forest Stewardship Council certified glassine paper. Some brands are decreasing the thickness and size of their polybags, a strategy called “lightweighting” that reduces the amount of plastic used.

Fashion for Good is trying to create a “circular” polybag made from a high percentage of post-consumer polybag waste. Existing recycled polybags, the organization says, rely predominantly on pre-consumer offcuts from the production floor that are mostly free of inks or adhesives that can contaminate the remanufacturing process. Fashion for Good is working with Spanish firm Cadel Deinking, a member of its Accelerator Programme, to strip post-consumer bags of their ink and adhesives, with the goal of creating a “suitably clear” recycled one for recirculation.

The clock is ticking for many businesses, however. Signatories of the Ellen MacArthur Foundation’s New Plastics Economy Global Commitment, which include brands and retailers such as Asos, Burberry, Stella McCartney, H&M and Zara owner Inditex, have pledged to eliminate “unnecessary and problematic” plastic packaging, ensure that remaining plastics are reusable, recyclable or compostable, and circulate all plastic items “in the economy and out of the environment” by 2025.