Scientists in Japan have developed an enzyme that converts ferulic acid from plant waste into vanillin, potentially revolutionizing the production of vanilla extract. This innovation could increase the availability and reduce the cost of this highly demanded ingredient.
Vanilla extract is widely used in food and cosmetics. It originates from vanillin, a compound found in vanilla plant seed pods from the orchid family. The enzyme VpVan in these plants converts ferulic acid into vanillin, giving vanilla its distinct flavor. However, synthesizing vanillin in a lab has been challenging, typically resulting in only small quantities.
Although inexpensive synthetic vanilla essences are available, they fail to replicate the true flavor of natural vanilla extract. Climate change has further limited vanilla plant growth, reducing supply despite high demand.
Researchers, whose findings were published in Applied and Environmental Microbiology, adopted a novel method to produce superior lab-made vanilla extract. Rather than imitating the VpVan enzyme, they engineered a new enzyme capable of converting ferulic acid into vanillin.
Professor Toshiki Furuya from the Tokyo University of Science explains that ferulic acid, derived from agricultural byproducts like rice bran and wheat bran, serves as a precursor for vanillin production. By combining ferulic acid with a specialized enzyme at room temperature, vanillin can be produced efficiently.
The researchers aimed to modify an enzyme named “Ado” to convert ferulic acid into vanillin. Typically, Ado adds an oxygen molecule to isoeugenol but cannot process ferulic acid in its natural state. Through computer modeling, they hypothesized that altering certain amino acids in Ado could enable it to interact with ferulic acid. Consequently, they created multiple Ado variants by substituting specific amino acids.
After experimenting, they created a mutant enzyme by replacing three amino acids: phenylalanine and valine with tyrosine and arginine. This new enzyme efficiently converted ferulic acid into vanillin. Notably, this engineered enzyme did not require any additional helper molecules (cofactors). It could produce a gram of vanillin per liter of solution simply by mixing it with ferulic acid and exposing it to air at room temperature.