Could shrimp shells replace plastic bags?

Every year, Egypt gets through 3500 tonnes of shrimp, producing around 1000 tonnes of leftover shells to get rid of. That’s about the same weight as 200 elephants! Now, a team of researchers working at universities in Egypt and England is investigating ways of turning this food waste into environmentally friendly plastic bags, as a way of helping the environment.

We use plastic for lots of things – shopping bags, drinks cartons and food packaging – and because only a small percentage is made from recyclable plastic, the majority of the stuff we throw away is either sent to landfill or ends up in the oceans.

Scientists estimate there are around 100 million tonnes of plastic in the Earth’s oceans. Because plastic can take up to 1000 years to break down, it remains a threat to wildlife for a long time. Sea turtles and other marine animals often mistakenly eat plastic bags, thinking they are jellyfish. The bags get stuck in their digestive systems, which can eventually kill them.

The research team has been working on tackling this problem by creating a plastic that will decompose quickly, without harming the environment. They break down and dissolve the cleaned shrimp shells to make a substance called chitosan (KY-toe-san). When dried, it produces very thin layers of biodegradable plastic. Although it’s possible to use the shells of other crustaceans (like crabs), it’s simplest to use shrimp, because their shells are thinner and easier to process in the laboratory.

While it takes centuries for plastic to fully decompose, biodegradable chitosan will completely break down in just two weeks. As it’s a type of plastic made from a natural material, it’s known as a bioplastic.

The team is only six months into a two-year project, so it will be a while before the “shrimp shell” bags are made available. This will give the researchers time to figure out how to make the bags as strong as regular plastic. So far, they’ve already calculated it will take less than 1 kilogram of shrimp shells to create up to 15 biodegradable bags. This means that the 1000 tones of shell that Egypt throws away will produce a mighty 15 million environmentally friendly bags per year. That’s a big step towards reducing our problem with plastic!

Watch Pollution: Air to learn more about other ways we are damaging our planet.