Researchers at the Tokyo University of Science have developed a gene-edited enzyme that can convert ferulic acid from upcycled wheat and rice bran waste into vanillin.
While vanillin is the preferred flavouring for many desserts and beverages, it is complex to create, requiring intensive cultivation techniques that magnify the ingredient’s production footprint.
The high market price of natural vanillin reflects the process required to grow the vanilla plants, cultivate and harvest the seed pods, and then extract the flavour. Added to the challenges, the cultivation of vanillin can only take place in a few very specific climates – Madagascar dominates global production – which creates supply chain vulnerability. Most artificial vanillin on the market is made from petrochemicals, which is not considered a clean label or sustainable source. Vanillin can also be synthesised from wood.
In response to these problems, this new alternative comes from a naturally-derived process and is also said to provide a highly sustainable and natural way of recreating vanillin at a far lower cost.
To date, scientists have managed to recreate vanillin using biosynthesis processes that rely on the conversion of ferulic acid using the same enzyme - VpVan - that creates vanillin naturally in plants. However, this process leads to very small yields of vanillin, making it impractical and expensive.
While there are cheaper synthetic vanillins on the market, an additional problem with these alternatives is that they rarely compare to the subtle but distinctive flavour of naturally-derived vanillin.
This conundrum prompted the Japanese research team to set about finding an enzyme that would outperform the VpVan enzyme, with the goal of re-creating a commercially viable yield with a good flavour, from a lab.
“Natural vanillin is sourced from the beans of the vanilla orchid through extraction,” explained said Professor Toshiki Furuya from the Tokyo University of Science. “However, the yield of vanillin is very low because it accumulates at low levels in the plant, making natural vanillin very expensive. Because our method produces vanillin from abundant agro-industrial wastes, it can be produced more cheaply than natural vanillin.”
In a study published in the journal of Applied and Environmental Microbiology, the research team explained how it was able to reproduce vanillin simply by mixing it with the upcycled ferulic acid and the enzyme that the team developed, at room temperature.
The researchers identified the enzyme Ado as being the most viable. It is an oxidase but in its natural state it does not have the ability to convert ferulic acid into vanillin. The team set about changing its properties by using genetic engineering approaches to develop mutant proteins that could enhance the conversion rate.
This enhancement to the enzyme took place using structural modeling analysis to predict the interaction and results that would happen once it interacted with the ferulic acid. The models helped the team to pinpoint the highest performing mutant protein, resulting in s high conversion activity that Professor Furuya says is both cost-effective and sustainable.
“This bioengineered vanillin is produced from natural ferulic acid found in commonly discarded wheat and rice bran waste, and it is then combined with the enzyme without using petroleum or chemical reagents. Thus, our method can provide food-safe vanillin,” said Professor Furuya.
The research team says that, do date, this is the first time an enzyme has been developed that can convert ferulic acid into vanillin at an industrial scale, suggesting that the results of the study could bear significant promise for the future of a vanillin that is significantly easier to produce.
Ultimately, the research team believes the results of this first study demonstrate the development potential the bioengineered enzyme has for a more viable, reliable and productive method of vanillin production in the future.
“We aim to industrialise this method within five years. With the goal of creating efficient industrial production of vanillin, we are attempting to further increase the activity of the enzyme,” said Professor Furuya.
