From chip shop to pit stop — scientists make old cooking oil biofuel as efficient as diesel

Published in Green Chemistry, researchers from King’s College London and Brazil’s National Laboratory of Bioregeneration used enzymes to break down fatty acids in cooking oil into olefins, which are the basic components of fuels such as gasoline and diesel. Scientists hope that new renewable fuels made from leftover food waste will reduce the use of fossil fuels.

Biofuels are a variety of energy sources made from renewable organic materials from plants or animals, such as vegetable oils. Fuels that can directly replace gasoline or diesel in traditional internal combustion engines are considered sustainable alternatives to fossil fuels, and fuels derived from food waste can reduce greenhouse gas emissions by up to 94%.

Typically, these fuels contain large amounts of oxygen molecules that burn inefficiently. This low fuel efficiency has previously hindered widespread use, with burning fatty acid-derived biofuels producing only 90% of the energy produced by diesel. To compensate and create diesel equivalents, more feedstock is needed, pushing costs up to twice those of fossil fuels.

Dr Alex Brogan, Senior Lecturer in Chemistry at the Department of Chemistry at King’s College London, said: “As a child I remember tins of oil sitting outside chip shops, which would soon be cut with diesel and then put in The back seat of the car, just in case.

“However, they will be an important way for industries such as logistics to transition away from fossil fuels, and without significant investment in the technology, countries like the UK will be further and further away from meeting emissions targets. What we have already done with the chemicals created is quite Because of the fossil fuels we use every day, it meets all the criteria that past chip shop fats couldn’t.

To create a more efficient fuel with more reactive olefins, the researchers modified an enzyme called P450 decarboxylase to break down fatty acids in food waste and extract oxygen from it.

The enzyme generally requires water to function, which means it produces lower yields of olefins. To overcome this problem, the modifying enzyme is put into liquid salt while shining UV light on it, mixing it with fatty acids to activate the reaction. This results in olefin yields that are much higher than those in water. Increased efficiency means less energy and raw materials are required to produce the fuel, significantly increasing sustainability.

Additionally, because the enzyme is a biocatalyst, the process does not require traditional catalysts such as platinum, thus avoiding any environmental damage caused by mining. Using UV light also prevents the use of toxic chemicals such as hydrogen peroxide to drive the reaction forward.

“Our (bio)technology allows us to expand to other renewable materials and produce a variety of fuels, including gasoline and kerosene for the aviation industry. We recognize that There is still much work to be done and I am excited to contribute to solving one of the world’s biggest challenges: climate change”

The team hopes that by building a method around the water requirements of P450 family enzymes, they can use the same technique to improve chemical reactions in different areas, such as in the efficient production of drugs.