Oil Change: Using Microbes to Produce Edible Oils

With the food system threatening to crumble under the weight of a growing population, Chris Chuck believes his alternative oil production technology can take some of the strain

CHRIS CHUCK entered engineering academia because he saw it as a chance “to make a real difference”. With an interest in biofuels and energy, he combined his passions as an independent research fellow in the chemical engineering department at the University of Bath, UK.

“I set out to look at sustainable technologies…and soon started realising that there was an enormous pressure for edible oils – for biofuels, for food, for surfactants – which we just couldn’t maintain as part of the current food system. There just isn’t enough land to do that,” he says.

One hectare of land produces around 3.8 t of palm oil, of which around 79.5m t was produced in 2023.¹ Total production of edible oils, which he notes have different land requirements, is around 250m t/y.

With the global population projected to increase to 9.8bn by 2050, Chuck anticipates that keeping up with current food system demand will necessitate cutting into virgin forests.

“But the major issue is greenhouse gases,” he stresses, citing evidence that supports emissions from oil production of 2,500–9,000 kg CO2e/t of lipid.^2,3,4

Now a professor at the University of Bath, and co-founder and technical lead at sustainable oils company Clean Food Group, he is developing precision fermentation as an alternative to existing practices.

With the global population projected to increase to 9.8bn by 2050, keeping up with current food system demand will necessitate cutting into virgin forests

More than a century in the making

When he began his research at Bath, Chuck says he and his industrial collaborators quickly realised there had been around 150 years of research into microbes that make oil. “Where are the amazing microbes which are making oil?” they questioned.

“One of the things we pinned down was that it’s really about the organism itself,” Chuck explains. Specifically that a lot of oil-producing microorganisms can’t be effectively scaled.

“So, we set out looking for an organism which, instead of making oil, was more suited for scalability.”

After a couple of years they found Metschnikowia pulcherrima, an organism that is almost ubiquitous around the world, able to grow on the surface of grapes and flowers. “It can use all sugars – monosaccharides, disaccharides, and oligosaccharides. It can break down those and proteins, and use that carbon, which is really useful for when you want to use low-cost feedstocks,” Chuck adds.

But the wildtype strains only produce a small amount of oil – 10–20% lipid content of its total dry cell weight, says Chuck. His group increased this to over 50% thanks to help from biologists and UK government funding, relying on directed evolution. Also known as laboratory evolution, the process involves mimicking natural selection to create the desired organism.

It’s this evolved version that Clean Food Group is working to commercialise, exploiting its ability to grow on low-cost feedstocks by feeding it sugars from wastes such as bread, whey, and lignocellulose from agricultural residues, grass, or silage. This reduces emissions from these wastes, as they are diverted from landfill or use in anaerobic digestion to produce biogas. More importantly, using waste as feedstock avoids the need to grow crops that also require land and ultimately increase net emissions.