Scientists Just Made Plastic Out of Salmon Sperm

As researchers look for ways to reduce the world’s reliance on plastic, an unlikely substance has turned out to be a key ingredient for an alternative to regular plastics: salmon sperm.

In a paper published on Nov. 14, a team of scientists at Tianjin University, in eastern China, detailed how they developed a bioplastic made with DNA from salmon sperm, among other chemicals.

According to the paper, strands of DNA from salmon sperm were dissolved in water and mixed with ionomers, a chemical that’s also found in adhesives, to create a gel that can be molded into various shapes—a process the scientists call “aqua-welding”—and then freeze-dried.

The end product is a material that resembles plastic, yet the process produces 97 percent less carbon emissions than manufacturing polystyrene plastics. The researchers said it is more environmentally sustainable than all existing types of plastics.

In the study, the scientists molded a small white mug and puzzle pieces with the material, called DNA plastic.

The entire production process of the innovative bioplastic is high on sustainability—from the extraction of raw material from biorenewable sources, to the fact that it can be broken down by enzymes when it’s discarded. DNA plastic is also very recyclable, since it can be softened with water and remolded into other shapes. 

The closed-loop recycling process of the bioplastic would “advance the development of sustainable materials,” according to the paper, published in the Journal of the American Chemical Society.

Every year, about 300 million tons of plastic are produced worldwide, a lot of which are single-use products with short lifespans but remain in landfills and natural habitats years after they’re disposed of.

The U.S. plastic industry is projected to overtake its coal counterpart to become the largest source of greenhouse gas emissions in the country by 2030, according to a recent report by U.S.-based initiative Beyond Plastics.

Bioplastics have emerged as a sustainable alternative to plastics. Made from organic materials like corn starch, sawdust, and food waste, bioplastics are often lauded for their smaller carbon footprint and their biodegradability (though not all bioplastics are biodegradable).

However, there are also doubts about whether existing bioplastics are as environmentally friendly as they seem. 

According to a bioplastic authentication paper written by scientists at GNS Science, a New Zealand-based research outfit, greenwashing and misrepresentation of the content of bioplastics is disturbingly common. Out of 37 products labeled as bioplastic, 19 were found by the scientists to fall short of their claims. In other words, they were simply engaged in greenwashing.

But the creators of DNA plastic are hoping that the material would one day enter the mass market. While salmon sperm was used in the research in Tianjin, the scientists said that the production process could draw from a wide range of DNA sources, such as fruits and algae. Mass production of DNA remains challenging, they noted, but not impossible.

“The potential of DNA that is rapidly and massively produced by the market is of great importance for future applications of DNA plastics,” they said.

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