Professor Michael Melkonian, algae specialist at the University of Cologne

Professor Michael Melkonian, algae specialist at the University of Cologne

Gaynor Selby writes in foodingredientsfirst.com that a team of scientists and researchers at the University of Cologne believe they have made a breakthrough that could lead to cultivating algae on a commercial scale in a much cheaper way than is currently possible.

Head of botany and algae specialist professor Michael Melkonian spoke with FoodIngredientsFirst about the potential upscale of algae production using a method that he his team has developed. “Let’s hope this is a breakthrough, I mean we are convinced but we need to convince others as well because it’s a real paradigm shift,” professor Melkonian said.

The “Porous Substrate Bioreactor” (PSBR), also known as the twin-layers system, uses a new principle to separate the algae from a nutrient solution by means of a porous reactor surface on which the microalgae are trapped in biofilms.

What is special about this new procedure, say the researchers, is that it reduces the amount of liquid needed in comparison to the currently used technology, which cultivates algae in suspensions, by a factor of up to one hundred.

The PSBR procedure thus allows for a significant reduction in energy and for an increase in the volume of algae that can be cultivated. “Our idea was that we make a very thin layer of biomass, a so-called biofilm. These biofilms exist in nature and they’re the most productive, based on biomass development.

“And where do we find these biofilms in nature? It’s simple,” said professor Melkonian. “Just look at a tree, you’ll see leaves, a leaf is an optimal structure for absorbing light and a leaf is only a millimeter in diameter. Evolution has already shown us what an optimal structure to absorb light looks like, namely it should be very thin.

“In this way we constructed a leaf and this is basically the technology behind it. It can use light efficiently and algae sit on a support material that could be paper or some kind of tissue or leaf like material, and they are wet and there is a nutrient solution inside this porous substrate, and they absorb light and take out carbon dioxide very efficiently because of the short path for both light and carbon dioxide.”

The scientific team at the University of Cologne has submitted an application for more funding from the national research ministry for a “proof of principle.” “In theory this system can be replicated and produced on a mass scale to produce high volumes of algae,” professor Melkonian said. “Of course, you cannot order a system tomorrow, because this is such a novel method, but there will be pilot systems in place; one of which is currently being installed in Spain.”

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