A joint Dutch and Chinese team has successfully converted corn into plastic using a method inspired by spider silk. The resulting corn protein-based biopolymer could offer a more sustainable alternative to fossil fuel-derived plastics, the team behind it believes.

Most plastics today are made from oil and gas, leading to several environmental issues, including carbon emissions and other pollutants. The use of plastics is also hugely wasteful, as plastic waste is very difficult to decompose in nature, leading to microplastics.

For this reason, scientists have been trying to find a biodegradable “bioplastic” alternative for years, especially plant-derived biopolymers. However, such “plastics” are weak, brittle, or are bad at keeping out moisture or oxygen.

This makes them impractical replacements for things like food packaging, fibers, or durable materials. “Plant-derived biopolymers may become sustainable alternatives to fossil-based polymers, yet their poor material performance has so far limited their adoption,” the team explained in its paper published in Nature Communications on May 11.

To this end, the team decided to look at corn protein called zein as a potential alternative. Zein already exists naturally in corn and is a byproduct of things like corn processing and ethanol production.

Made from corn, inspired by spiders

This material is both biodegradable and renewable, but (like other plant-derived plastics) is weak, fragile, and not very useful industrially. To overcome this, the team took inspiration again from nature by looking at how spiders make silk for their webs.

Spider silk is famously extremely strong, flexible, lightweight, and biodegradable. If s similar material could be replicated using zein, then the resulting biopolymer could open up interesting possibilities to replace plastic.

Spiders process protein in interesting ways when spinning silk, and the team set out to replicate it as closely as possible. When spiders produce silk, the glands in their abdomen alter water content, control acidity, align proteins, and effectively reorganize molecular bonds.

This results in a very strong internal structure in the silk, making it (pound for pound) one of the highest tensile strength materials on Earth. Instead of simply melting or chemically processing the corn protein like normal plastics, the team used a silk-inspired method to reorganize the protein molecules.

That caused the zein proteins to line up and bond more effectively. It is this alignment that makes the new biopolymer so strong. Using this new polymer, the team produced fibers, thin sheets, and film to form something they’ve dubbed “plantymer.”

This material is strong and right, acts as a great barrier against water and oxygen, and, critically, is biodegradable. According to the team, as much as 80% of it can decompose when exposed to soil within one month.

Could it replace plastic?

While interesting, it is important to note that this is still very much in its research and development phase. There are still many unknowns that need to be answered before it could ever challenge conventional plastics.

For example, can production be scaled outside of a lab? Can enough zein be produced without impacting food production? How durable is “plantymer” over time? How does it react to heat and light exposure over time? Does it have any utility in industry?

Whatever the case, the new material is certainly a step in the right direction. “We have shown that processing protein materials inspired by spider silk can be applied to amply available plant proteins such as zein from corn,” the team added.

You can view the study for yourself in the journal Nature Communications.