Solve Invasive Seaweed Problem by Turning It into Biofuels and Fertilisers

Algae/Other Aquatic Organisms/Seaweed Feedstock Feedstocks Not Agriculture Process R & D Focus Sustainability UK (United Kingdom)University/College Programs

May 13, 2020

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(University of Bath/Phys.Org) UK researchers have developed a cheap and simple way of creating biofuel and fertiliser from seaweed, whilst removing plastic from the oceans and cleaning up tourist beaches in the Caribbean and Central America.

Millions of tonnes of rotting seaweed washes up on beaches of Mexico, the Caribbean and elsewhere every year.

Partly fuelled by fertilisers washing into the sea from farming in the Americas, the foul-smelling Sargassum seaweed devastates the tourism industry and harms fisheries and ocean ecosystems.

A research team, led by the University of Exeter and the University of Bath, has developed a cheap and simple way to pre-process seaweed before making bulk chemicals and biofuels from it.

Making biofuels financially viable

"Ultimately, for this to work it has to make financial sense," said Professor Mike Allen, from the University of Exeter and Plymouth Marine Laboratory.

"Processing marine biomass like seaweed usually requires removing it from the salt water, washing it in fresh water and drying it.

"The costs of these processes can be prohibitively high.

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Using acidic and basic catalysts, the team devised a process that releases sugars that can be used to feed a yeast that produces a palm oil substitute. The same method also prepares the residual seaweed for the next stage of processing, called hydrothermal liquefaction.

This process subjects the organic material to high temperature and pressure, turning the seaweed into bio-oil that can be processed further into fuels, and high-quality, low-cost fertiliser.

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Not only is all the seaweed used in products, but any plastic collected alongside the seaweed will also be converted alongside the seaweed. Part of the inspiration for the project came from Professor Allen's children, Rosie (12) and Archie (9), who helped collect seaweed samples for trial studies from the Devon coast.

Professor Allen said: "It was Rosie who triggered a whole stream of research following the painstaking removal of plastic litter from the children's seaweed samples by asking: 'Dad, can't you just convert the plastics alongside the seaweed?'"

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This is the latest in a string of developments around seaweed processing from the team which is supported by UKRI, Global Challenges Research Fund, Roddenberry Foundation, Innovate UK and Newton Fund. Exploiting their diverse expertise in phycology, chemistry, ecology, biotechnology and chemical engineering, they are now seeking to develop seaweed based biorefineries to provide local solutions and opportunities on the global stage. READ MORE includes VIDEO