Researchers have shown that Greek yoghurt could be an unlikely source of sustainable jet plane fuel. They found out that there’s a way to turn waste products from yoghurt production into a raw material for livestock feed additives and biofuel.
The main constituents derived from the manufacturing process or whey is mostly the milk sugar lactose, the sugar fructose and lactic acid. Researchers used bacteria during the study to turn the cocktail into an extract containing the useful compounds caproic acid and caprylic acid.
The results showed that both compounds qualified as 'green antimicrobials' that could be added to livestock feed to replace standard antibiotics. The scientists also revealed that after further processing to add more carbon elements to the compounds, they could yield a 'drop-in' biofuel that can be mixed into jet fuel.
A statement released by the Lead researcher Dr. Lars Angenent, from Cornell University, New York, revealed that: '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 yoghurt 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'.
'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 whole traditional idea of suppressing oxygen while feeding biodegradable waste to microbes results in the production of methane-rich gas through anaerobic digestion was not deployed. Alternatively, the researchers strung together two 'open-culture' reactors.
The researchers used two bio-reactors in which yoghurt whey was seeded with bacteria. The first tuned for heat-loving microbes fond of temperatures of 50°C, the second set at a more welcoming 30°C mark.
The next challenge will be to see what happens when the twin bioreactor system is boosted to pilot plant capacity.
The researchers ought to learn how to optimize the extraction process and scale up economically as Dr Angenent emphasized.