Researchers turn seaweed into biofuels and fertilisers

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, announced a statement.

“Ultimately, for this to work it has to make financial sense,” said Professor Mike Allen, from the University of Exeter and Plymouth Marine Laboratory, in the statement. “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. We needed to find a process that would pay for and sustain itself – something both economically and environmentally viable.”

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.

Not only is all the seaweed used in products, but any plastic collected alongside the seaweed will also be converted alongside the seaweed.

Another strength of the plan is its use of invasive seaweed such as Sargassum – an environmental nuisance which currently costs the tourist industry vast sums, both in clean-up costs and because it deters visitors.

Photo credit: Kevin Doncaster/ Flickr CC BY 2.0

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