Scientists Made an Eco-Friendly Plastic Using DNA From Salmon Sperm

Researchers in China have designed an alternative to plastic using an unlikely source: salmon sperm.

The plastic-like material is formed when two short strands of salmon DNA are combined with another chemical derived from vegetable oil. The result is a gel-like squishy substance called a hydrogel. Details about the bioplastic were published last month in the Journal of the American Chemical Society.

After freeze-drying to remove any moisture, the hydrogel can be molded into different shapes. Scientists have already created puzzle pieces, a cup, and a plastic DNA model from the material using a process they call aqua-welding, reports Molly Taft for Gizmodo. Compared to traditional polystyrene plastics, the new bioplastic requires 97 percent fewer carbon emissions to make, reports Koh Ewe for Vice.

Oil-based plastics require tons of heat and toxic substances to manufacture and take hundreds of years to break down. While marketed as recyclable, most plastic objects end up incinerated or thrown into landfills, reports Rosie Frost for EuroNews Green. 

To recycle the new bioplastic, DNA-digesting enzymes can be added to break the material down. If no enzymes are available, simply submerging the sperm-derived substance into water will turn the object back into a slop of hydrogel, Gizmodo reports. So, using the material for holding a cup of tea or holiday eggnog may not be the best idea.

However, the researchers insist it is the most sustainable material compared to other known plastics. Other biodegradable bioplastics from algae, cornstarch, sawdust leave behind a small carbon footprint over their lifetime compared to than regular oil-based plastics, but creating these materials still requires energy provided by the fossil-fuel energy grid. So, there’s debate over whether these types of bioplastics are genuinely environmentally friendly, Gizmodo reports.

Bioplastic manufacturers may also be greenwashing and misrepresenting what their bioplastics contain, per Vice. After analyzing 37 products labeled as bioplastic,19 were found to be made from both petroleum and bio-based mixes, according to a study conducted by the New Zealand–based private research company GNS Science.

Because the salmon sperm bioplastic is made from DNA strands, this type of plastic can be derived from a variety of DNA sources, like plants or bacteria, per EuroNews Green.

There are about 6.3 billion tons of plastic trash on the planet, Gizmodo reports. Despite its water-resistant limitations, researchers are hopeful that this plastic made from salmon sperm could help reduce plastic waste if it enters the market.

Elizabeth Gamillo | | READ MORE

Elizabeth Gamillo is a daily correspondent for Smithsonian and a science journalist based in Milwaukee, Wisconsin. She has written for Science magazine as their 2018 AAAS Diverse Voices in Science Journalism Intern.