glass of caviar

Scientists Use Salmon Sperm to Make Plastic

Caviar-lovers be warned of bare blinis.

Salmon sperm is now the key ingredient in an innovative “natural” plastic.

A team of Chinese scientists extracted DNA from salmon testes and mixed it with vegetable oil. The resulting hydrogel is soft and malleable. The process then involves freeze-drying the gel to remove all water. This allows it to solidify. It can then be molded into different shapes. So far, researchers have created cups, bowls, puzzle pieces, and even a DNA molecule. 

Significantly, the entire production process creates less than 5% of the carbon emissions released in traditional plastic manufacture. Plus, the end result is 100% recyclable. By placing the natural plastic in water, it can be broken down by DNA digesting enzymes. As it reverts back to a hydrogel, it can be made into a new item. The team of scientists created their raw materials from salmon sperm DNA. As there are around 50 billion tonnes of DNA on the planet, this means that technically plastic could be made from other sustainable sources. These include crop waste, algae, or bacteria.

DNA-mazing

According to a recent United Nations Environment Programme analysis , the world produces in excess of 380 million tons of plastic each year.  As a result, around 8 million pieces of plastic make their way into the ocean. Here, they pollute waterways, animals, and even drinking water. Equally, the plastic manufacturing process requires huge amounts of heat and toxic substances. Whilst biodegradable plastics have already been created using materials like cornstarch and algae, they still need a lot of energy to make. Plus, they can be difficult to recycle.

Dayong Yang and his team at Tianjin University wanted to create a material that solved these problems.  “’Plastics play important roles in modern life and currently the development of plastic recycling is highly demanding and challenging. To relieve this dilemma, one option is to develop new sustainable bioplastics that are compatible with the environment over the whole material life cycle,” the Chinese scientists’ report explains. Published in the Journal of the American Chemical Society, it continues, “This work provides a solution to transform biobased hydrogel to bioplastic and demonstrates the closed-loop recycling of DNA plastics, which will advance the development of sustainable materials.”

The fact that the bioplastic can be recycled using water alone means it does need to be kept dry. While waterproof coatings could be added, this would impact recyclability. It could, however, be used for items like electronics that need to be kept dry anyway and some forms of packaging, the researchers believe.

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