TK Dandelions and guayule shrubs are being extracted for rubber by Ohio State researchers. Credit: Dr. Katrina Cornish, professor of horticulture and crop science
Ohio State scientists are working to increase rubber production in the U.S. by researching ways to make the extraction of latex from dandelions and desert shrubs more efficient as threats of plant disease in South America loom over the international rubber market.
Lead researcher Katrina Cornish, a professor of horticulture and crop science, said she hopes her research will help the U.S. become independent in the rubber industry and will fulfill her 30-year dream of creating a rubber processing plant that uses both the “Taraxacum kok-saghyz (TK) dandelion” and the “guayule shrub” — two species typically used in rubber production.
Latex is derived from the bark of rubber trees, which predominantly reside in South America, but were able to be cultivated in Southeast Asia, though at an increasing environmental cost, according to the East-West center.
In order to do this, Cornish and fellow researchers “have added specialized agents during processing” of both the TK dandelion and the guayule shrub in order to “coax” more latex from both plants, according to an Ohio State news release.
“You want to get binds and soluble proteins out in one step if you could, not three or four steps, because each of those increases the costs and the time of separation, and at each step, you will lose some rubber particles,” Cornish said.
The U.S. currently does not produce its own rubber, importing nearly a million tons of the raw material from Southeast Asia and West Africa per year, along with already-produced tires and gloves, Cornish said.
The country’s dependence on foreign imports of rubber is an issue if leaf blights from South America were to infect the rubber trees in other parts of the world. Leaf blights are the main fungal disease that threatens natural rubber production, according to the National Institute of Health.
“Back in 2019, in the last six months of that year, we lost 10% of our trees due to blights that jumped over from oil palm,” Cornish said. “It only took six months for over a million acres across seven countries to become diseased.”
Cornish said both the process for extracting rubber from the TK dandelion and the shrub begin by grinding up the section of the plant that contains the latex: the bark of the guayule shrub and the roots of the TK dandelion. After the grinding, both plants have become what Cornish refers to as a “milkshake-like” consistency that is then washed and filtered to retrieve the latex.
When flocculants — chemicals that cause the clumping of solids — are added to the guayule shrub “milkshake,” the particles in the mixture are easier to separate from the latex, making the process quicker and increasing the amount of product that can be extracted, Cornish said.
TK dandelions, on the other hand, are trickier because they produce rubber particles that are heavier than water, making it difficult to extract the material, Cornish said.
After leaving a TK dandelion mixture in the fridge for three months, researchers discovered that there was latex floating on top of the slurry, meaning that it was possible to make the material lighter, Cornish said.
Through more analysis, the researchers found that particles such as magnesium would bind to the rubber, causing it to sink, Cornish said.
“We can make the even heavier [rubber particles] lighter by treating it with [a material that strips], which stripped off these little metal jackets that it was wearing,” Cornish said.
Despite the differences in the processes, the end product of both plants is similar to that from Hevea brasiliensis, the tree where most natural rubber comes from, Beenish Saba, a postdoctoral researcher in food, agricultural and biological engineering at Ohio State and a researcher on the project, said.
“It’s good quality,” Saba said. “It can be used more in medical equipment as compared to [rubber from Hevea brasiliensis]. When we compare the rubber characteristics like stretchability and strength, it’s comparable.”
