Scientists at the University of California San Diego have developed a new method to produce large quantities of xanthommatin, a pigment responsible for the camouflage abilities of cephalopods such as octopuses, squids, and cuttlefish. This pigment allows these animals to change their skin color and blend into their surroundings.
The research team from UC San Diego’s Scripps Institution of Oceanography used a nature-inspired approach to generate the pigment in bacteria. Their method yielded up to 1,000 times more xanthommatin than previous techniques, which traditionally produced only small amounts through labor-intensive chemical synthesis or inefficient extraction from animals.
“We’ve developed a new technique that has sped up our capabilities to make a material, in this case xanthommatin, in a bacterium for the first time,” said Bradley Moore, senior author of the study and marine chemist with joint appointments at Scripps Oceanography and UC San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences. “This natural pigment is what gives an octopus or a squid its ability to camouflage — a fantastic superpower — and our achievement to advance production of this material is just the tip of the iceberg.”
The study was published on November 3 in Nature Biotechnology and received funding from several organizations including the National Institutes of Health and the Office of Naval Research.
Xanthommatin is also found in insects like monarch butterflies and dragonflies, contributing to their vibrant colors. The challenge in studying this pigment has been due to difficulties in obtaining sufficient quantities for research or industrial use.
To address this supply issue, researchers implemented what they called “growth coupled biosynthesis.” They engineered bacteria so that their survival depended on producing both xanthommatin and formic acid; each molecule of pigment generated would be accompanied by one molecule of formic acid necessary for cell growth. This self-sustaining loop encouraged high-yield production.
“We needed a whole new approach to address this problem,” said Leah Bushin, lead author now at Stanford University but formerly at Scripps Oceanography. “Essentially, we came up with a way to trick the bacteria into making more of the material that we needed.”
Further optimization involved robotic evolution campaigns developed by Adam Feist’s lab at UC San Diego Jacobs School of Engineering. These efforts allowed identification of genetic mutations that increased efficiency so bacteria could produce xanthommatin directly from simple nutrients.
“This project gives a glimpse into a future where biology enables the sustainable production of valuable compounds and materials through advanced automation, data integration and computationally driven design,” said Feist. “Here, we show how we can accelerate innovation in biomanufacturing by bringing together engineers, biologists and chemists using some of the most advanced strain-engineering techniques to develop and optimize a novel product in a relatively short time.”
Traditional methods typically yield about five milligrams per liter; however, this new technique produces between one to three grams per liter—a significant improvement according to Bushin.
Moore believes that this biotechnology could transform biochemical manufacturing: “We’ve really disrupted the way that people think about how you engineer a cell,” he said. “Our innovative technological approach sparked a huge leap in production capability. This new method solves a supply challenge and could now make this biomaterial much more broadly available.”
There is interest from various sectors including defense agencies looking into camouflage applications as well as cosmetics companies exploring its use as natural sunscreen or UV protectant. Other possible uses include color-changing paints or environmental sensors.
“As we look to the future, humans will want to rethink how we make materials to support our synthetic lifestyle of 8 billion people on Earth,” Moore added. “Thanks to federal funding, we’ve unlocked a promising new pathway for designing nature-inspired materials that are better for people and the planet.”
Other contributors included researchers from UC San Diego departments as well as collaborators from Northeastern University and institutions in Denmark.
