Seaweed coffee cups could help ditch single-use plastics

A sizable portion of the plastics we use on a single occasion end up in our oceans. As more people abandon these plastics, seaweed — also known as macroalgae — and microalgae may be the answer to the world’s plastic food packaging problem. These materials are being used to create everyday items ranging from edible water bottles to coffee cups and biofuels.

According to UN Environment’s report on single-use plastics, we produce more than 400 million tonnes of plastic annually on a global scale. Packaging that is discarded after a single use accounts for 36% of all plastic produced globally, making it the largest industry producing plastic. The majority of this waste is generated in Asia. However, the United States of America (US), Japan, and the European Union (EU) generate the most plastic packaging waste per person.

According to a 2016 World Economic Forum report, by 2050, there may be more plastic in the sea than fish if current production trends continue.

‘The effects of plastic on the environment are becoming increasingly obvious,’ said Rodrigo Garca González, co-founder and co-CEO of UK start-up Skipping Rocks Lab. ‘Society is becoming more aware that this is a significant problem for which institutions, businesses, and consumers must find solutions.’

Skipping Rocks Lab’s mission is to develop waste-free alternatives to single-use plastics such as bottles, cups, and plates by utilising natural materials extracted from plants and seaweed. In 2013, it launched its first product, Ooho, a brown seaweed-based edible water bottle.

Garca González and his team are now working on a project called UCUP in which they hope to use brown seaweed to create a sustainable paper cup for takeaway drinks.

‘You use a coffee cup for no more than a half hour and it will remain in the environment for probably 700 years. That is a significant mismatch in terms of use and shelf life,’ Garca González explained.

The concept is to use seaweed as a biodegradable, recyclable, and waterproof container in disposable food packaging.

‘You use a coffee cup for no more than a half hour and it will remain in the environment for probably 700 years. This is a significant mismatch in terms of intended use and shelf life.’

Seaweed lining, Rodrigo Garca González, co-founder and co-CEO, Skipping Rocks Lab

To this day, paper cups are frequently lined or coated with plastic such as polythene (PE) or petroleum-based waxes to prevent liquid from leaking out or soaking through the paper. As a result, Garca González notes, they are difficult to recycle.

In addition, cups that claim to be 100% biodegradable or compostable are usually made from polylactic acid (PLA), a polyester derived from renewable resources such as starches, which still takes a long time to break down.

‘PLA is compostable but only in industrial compostable sites, so you need to identify that cup and bring it to a special facility that is going to apply specific pressure, heat and ionic liquids in order for it to start to decompose,’ said García González. ‘If not, nothing will occur.’

Rather than that, seaweed packaging decomposes in about four to six weeks in soil. As seaweed is cheap, easy to harvest and extract, and is available on every coastline, it could replace the plastic liner inside most takeaway cups and provide the same properties as current oil-based ones at competitive prices.

‘Seaweed is one of the fastest organisms on the planet to grow,’ said García González. ‘Some seaweeds can reach a growth rate of up to a half metre per day.’

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