Fungal fermentation offers the promise of low-cost omega-3s

Fungi could serve as a more cost-effective source of omega-3 fatty acids than fish or microalgae, according to researchers at CABI: a not-for-profit organisation housing one of the world's largest collections of fungi.CABI's collection includes 450 fungi from the British Antarctic Survey known as 'extremophiles', several of which were likely to be able to synthesise omega-3 fatty acids given their ability to thrive in extreme conditions, said director of biological resources David Smith. A PhD student from the Royal Holloway University of London tasked with exploring the potential of fungi as novel sources of nutraceuticals had also identified several fungi in CABI's main collection that could produce EPA (eicosapentaenoic acid) and ALA (alpha-linolenic acid), said Smith.

It was highly likely that fungi capable of producing DHA (docosahexaenoic acid) would also be found, given that there were 1,000s of strains yet to be screened, he said. "We are looking for better producers of omega-3s [than fish or microalgae]. Microalgae need light, whereas fungi don't, so a bioreactor for fungi should be simpler and more cost-efficient."

Omega-3 supplier Martek Biosciences currently makes most of its DHA for food from an organism called Schizochytrium, which is classified as a thraustochytrid. These used to be regarded as fungi, but are now described as microalgae. While Martek makes arachidonic acid (omega-6) from the fungus Mortierella, the only viable source of omega-3s at the moment was microalgae, said senior scientist Casey Lippmeier. "We are constantly investigating new organisms with the potential to improve on this. But they would have to offer increased productivity before they could be developed commercially."

However, Adam Ismail, executive director at omega-3 trade association Goed, said fungal production clearly had potential: "The value proposition would be similar to algal oil: a vegetarian source of omega-3. Specifications could also be tightly controlled.

"Also, algal fermentation only produces DHA today; EPA has not been seen at a truly commercial scale yet. If you could make oil from fungi with EPA and DHA, they would be able to compete more directly with fish oils. But fermentation kit is expensive, so any organism must be very productive in order to get a good return on investment."