Greek yogurt could be an unlikely source of sustainable jet plane fuel, researchers have shown.

Scientists have found a way to turn waste products from yogurt production into a raw material for biofuel and livestock feed additives.

Whey left over from the manufacturing process mostly consists of the milk sugar lactose, the sugar fructose and lactic acid.

For the study, bacteria were used to turn the cocktail into an extract containing the useful compounds caproic acid and caprylic acid.

Further processing to add more carbon elements to the compounds could yield a "drop-in" biofuel that can be mixed into jet fuel, said the scientists.

Both compounds qualified as "green antimicrobials" that could be added to livestock feed to replace standard antibiotics.

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US lead researcher Professor Lars Angenent, from Cornell University, New York, said: "To be sustainable, you want to convert waste streams where they are made, and upstate New York is where the cows are, where the dairy farmers are, and where the Greek yogurt craze began in the United States.

"That's a lot of acid whey that right now has to be driven to faraway locations for land application, but we want to produce valuable chemicals from it instead."

He pointed out that while the agricultural market was smaller than the fuel market, it had a "very large carbon footprint".

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"Turning acid whey into a feedstock that animals can eat is an important example of the closed cycles that we need in a sustainable society," he said.

The team, whose work is published in the journal Joule, used two bio-reactors in which yogurt whey was seeded with bacteria.

The first was tuned for heat-loving microbes and the second for bugs that preferred lower temperatures.