Vanilla extract and raw vanilla beans (Photo by Africa Studio on Shutterstock)
TOKYO — Move over nature, there’s a new way of making vanilla extract. As many bakers know, the demand and price for this sweet and pleasant-smelling ingredient is always sky-high. Now, scientists in Japan have created an enzyme that helps convert ferulic acid from plant waste into vanillin. The breakthrough could soon make this popular product more available than ever before.
Vanilla extract is popular in both food and cosmetics. It naturally comes from the chemical compound called vanillin found in the seed pods of vanilla plants in the orchid family. Vanilla is created when the plant enzyme VpVan converts ferulic acid into the vanilla-flavored compound. However, replicating this process in the lab has proven difficult, with the synthetic process only producing small amounts of vanillin.
While cheap, chemically-derived vanilla essences do exist today, they do not accurately mimic the flavor of natural vanilla extract. Climate change has also hampered the growth of vanilla plants, leading to a low supply despite high demand.
The study authors, who published their work in Applied and Environmental Microbiology, decided to take a different approach to create better lab versions of vanilla extract. Instead of trying to replicate the VpVan enzyme, they developed a brand-new enzyme that does the same job of transforming ferulic acid into vanillin.
“Ferulic acid, the raw material, is a compound that can be obtained in abundance from agricultural waste such as rice bran and wheat bran. Vanillin is generated simply by mixing ferulic acid with the developed enzyme at room temperature. So, the established technology can provide a simple and environmentally friendly method for producing flavor compounds,” says Toshiki Furuya, a professor in the Department of Applied Biological Science at the Tokyo University of Science, in a media release.
The researchers wanted to modify an enzyme called “Ado” so that it could convert a compound called ferulic acid into vanillin. Normally, Ado's job is to add an oxygen molecule to a different compound called isoeugenol. Ado can't work with ferulic acid in its natural form.
Using computer modeling, the researchers predicted that if they changed a few of the amino acids (which are like the building blocks that make up the enzyme), Ado might be able to interact with ferulic acid properly. So, they made various versions of Ado with different amino acids swapped in at specific positions.
After some trial and error, they found a mutant version where they replaced just three amino acids — phenylalanine and valine with tyrosine and arginine. This new mutant enzyme could stably convert ferulic acid into vanillin really efficiently.
The really cool thing is that the engineered enzyme didn't need any extra helper molecules (called cofactors) that other enzymes often require. It could make a gram of vanillin per liter of solution just by mixing it with ferulic acid and exposing it to air at room temperature. That's a pretty simple, sustainable, and cost-effective process for making larger quantities of vanilla extract at cheaper prices!
Even better, this mutant enzyme could also convert some other similar compounds like p-coumaric acid and sinapic acid, which come from breaking down lignin. This waste product is left over from agriculture like plant stalks and woody materials. So, this enzyme could also put those waste products to good use.
“Harnessing the potential of microorganisms and enzymes to derive valuable compounds under mild conditions from renewable plant-based resources, offers a sustainable approach to minimizing environmental footprint,” explains Furuya. “Presently, in collaboration with a company, our research endeavors focus on achieving the real-world implementation of vanillin production through the utilization of the newly developed enzyme.”
