Your next sunscreen could be made from E. coli

Let’s face it, sunscreen is important to our health, but can really be a drag. Some feel greasy, they wear off after only two hours, and finding the right one can feel like a game of whack-a-mole. Certain ingredients can also pollute the planet’s critical coral reefs, so scientists around the world are looking to nature to create new formulas. Pollen could serve as an eco-friendly sunscreen solution, but there could be an even smaller source—bacteria. Escherichia coli, better known as E. coli, may help create an ultra violet (UV) compound that can be used in sunscreens. The findings are detailed in a study published today in the journal Trends in Biotechnology.

To survive relentless sunlight in the open ocean, fish can make their own natural sunscreen with a UV-protective compound called gadusol. This rare molecular compound is found in the eggs of several fish species, but is scarce elsewhere in nature and not easy, efficient, or environmentally friendly to extract. 

“We want to find a scalable and greener way to produce gadusol,” Ping Zhang, a study co-author and biochemist at Jiangnan University in China, said in a statement. 

Zhang and the team turned microbes into mini chemical factories, instead of taking them from nature. To do this, they rebuilt a zebrafish’s pathway for making gadusol inside of an E. coli bacterium. They then tweaked the E. coli’s genetics and growing conditions. The alterations increased the gadusol yield by nearly 93 times—from 45.2 milligrams per liter up to 4.2 grams per liter. The lab-made compound is also showing promise in early UV-protection tests. 

“Achieving this level of production in the lab is very promising,” says Zhang. “It suggests that we may be able to meet future demand for natural sunscreen ingredients through microbial production.” 

In other experiments, gadusol showed that it may offer more than just protection from the sun. It showed antioxidant activity comparable to vitamin C, suggesting that gadusol may help neutralize cell-damaging free radicals that can result from excess sun exposure. 

These antioxidant properties also inspired a color-based screening test that allows researchers to quickly identify bacterial strains that produce more gadusol. When the gadusol neutralizes free radicals, a purple chemical signal turns yellow, indicating that it is producing more of the UV-protective compound

“Compared with traditional chemical analysis, this approach is more convenient, efficient, and economical,” added study co-author and Jiangnan University bioengineer Ruirui Xu.

While gadusol’s combination of UV protection and antioxidant activity could make it an attractive natural ingredient for future sunscreens, it won’t join your next beach day just yet. The study didn’t compare gadusol head-to-head with currently available sunscreens, or assess its long-term safety or large-scale manufacturing. Before it can hit store shelves, it will also require regulatory approval. 

However, Xu believes that this is a starting point for using gadusol in practical applications. Based on current technology, he expects that some products using gadusol could appear on the market within two years.  

“For small molecules with application potential, we hope people look beyond traditional extraction methods,” said Zhang. “Microbial cell factories are emerging as a greener and more sustainable way to bring laboratory discoveries into real-world use.”

 

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