The flavour and scent of a grapefruit has been conjured up by scientists, but from a different fruit – an orange.
Nootkatone is the molecule which gives this distinctive aroma, and is used worldwide in foods, drinks, and bathroom products. However, it takes around 400,000kg of grapefruit to produce 1kg of nootkatone, making it one of the most expensive ingredients in the world. It is also heavily reliant upon a good harvest, in an industry which is very sensitive to weather and disease.
Synthesising the plant terpene in a lab also poses a significant challenge, as this process uses some of the most complex reaction pathways observed in biology.
The University of Oxford spin-out company, BioTrans, looked to oranges as a way to improve production while avoiding man-made chemicals. They found that oranges produced a very similar compound, valencene, which when treated with a specially modified cytochrome P450 enzyme, was oxidised to nootkatone.
This new method complies with EU regulations for ‘natural’ flavourings, and is vastly cheaper, as the supply of valencene is plentiful, even in years of poor orange harvest. The compound is found in the essential oil of oranges, a by-product of the juice industry.
James Brown, Synthetic Biology Lead, UK Knowledge Transfer Network said: “There are immense opportunities for the UK to lead the way in this technology. We are developing novel ways to produce high-value natural compounds without having to disrupt natural habitats or use manmade toxic chemicals that require careful disposal.”
“We’re at the start of bringing industrial processes into the 21st century, using our knowledge of engineering and biology in a sustainable and distributed manner. It’s very exciting for the field and for the UK bio-economy.”
Follow the link to an infographic produced by BioTrans