A Paradigm Shift in Microalgal Biotechnology Could Be On The Cards Thanks To A University of Cologne Breakthrough

18 Jul 2016 --- A team of scientists and researchers at the University of Cologne believe they have made a breakthrough which 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 speaks with FoodIngredientsFirst about the potential upscale of algae production using a method that has been discovered by him and his team.

“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. We’re looking at small algae, so small you can only see them through the microscope. Small organisms that use sunlight to produce biomass.”

Biofuels are used in cosmetics, pharmaceutical sciences and aquafarming, however the main problem is people struggle to grow it cheaply enough to open large markets like the food and and feed market or bioenergy market.

Microalgae hold tremendous potential for industrial biotechnology and are an important resource in the production of food and medications. In comparison to bacteria and fungi, they still only play a minor role.

The economic use of these organisms has been limited because of the high production costs involved, but thanks to Professor Melkonian’s research, this could now change.

“The reason is very simple; if you add sugar to a cup of coffee it dissolves within seconds and every sugar molecule is evenly distributed and three dimensional in your cup. This is the principle of the fermenter and the fermenter is used in microbiology which is used to grow bacteria and fungi,” he explains.

“However, if you want to grow algae the energy is sunlight or an artificial light source and light always comes from a source and therefore you cannot distribute the particles of light in three dimensions.”

“Since the algae are colored green, blue or whatever, they absorb certain parts of the spectrum of light and therefore the next algae that sits behind the one that absorbed the light particle does not get light any more.”

Many years of research work on the development of photobioreactors, which use photosynthesis to turn light energy into biomass, have preceded this success. 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 is that is 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. Current success in PSBR development and the rise in interest in this technology in recent years could signal a turn in the conception of future photobioreactors in microalgae biotechnology.

“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; 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.”

Now the scientific team at the University of Cologne know how to go about producing much higher levels of algae on a tighter budget, what happens next?

“I am due to retire next year, but the younger people here will take it forward. An application will go in for more funding from the national research ministry and early next year we will hear if we get the funding for a proof of principle.”

“In theory this system can be replicated and produced on a mass scale to produce high volumes of algae. 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.”

“I must say that I’m optimistic and expect the technology to be used in five years or so. Whether algae can be used to produce energy, I doubt it, because the production costs have to be much less, but if we are lucky we can enter the food and feed market and animal feed market.”

by Gaynor Selby

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