ÖkoPro meeting at Spranger

Among other things, blue bioeconomy means relieving the element “water” of excessive nutrient input while at the same time operating as sustainably and profitably as possible. In the BMBF-funded innovation space “Bioeconomy at Marine Sites” (BaMS e.V.), specialized consortia from research and industry are addressing the challenges posed by this topic in the form of research projects.

One highly interdisciplinary project from this innovation space is ÖkoPro, led by Sascha Hermus from the Lower Saxony Network for Renewable Raw Materials and Bioeconomy (3N).

“We will convert waste heat, CO2, and previously problematic water-soluble nutrients from the surface water of biogas plants into the highest possible quality biomass using microalgae,” says Hermus about the project's goals.

What is particularly new here is the intention to utilize microalgae biomass in ways that go beyond its use as a substrate in biogas plants or as a fertilizer additive, as is the case in the ÖkoPro project. The toxicology department at Kiel University will help to clarify exactly which utilization options are feasible. Preliminary investigations by the working group led by Prof. Dr. Edmund Maser have already shown good purification results for all tested “problem water” from sewage treatment and agriculture. Approval for use in pet food or natural cosmetics is therefore definitely conceivable. Experts from these industries, namely Microganic GmbH from Melle and the Kiel-based company oceanBASIS, are responsible for investigating the possible uses of algae in the project.

(Image above: Svenja Starke, Microganic)

“It's a long way from the idea to the bioeconomic product,” explains algae expert Prof. Dr. Rüdiger Schulz from the Botanical Institute at Kiel University. “Choosing the right type of algae will be crucial.” This determines the conversion rate of toxic substances and the usability of the biomass.

The design of the microalgae reactor is also crucial for the growth and yield of the algae harvest, and thus also for the expected purification performance. This is still an absolute niche market that offers hardly any “off-the-shelf” solutions.

The ÖkoPro team therefore met at the end of April 2022 in Plauen (Saxony) with plastics specialist Andreas Spranger. The 11-member consortium from all over Germany was welcomed with great hospitality and given a tour of the premises.

The highlight of the meeting was the demonstration of the prototype of the “Christmas tree” (filled with tap water for leak testing) – a novel production unit in microalgae culture presented by Dr. Martin Ecke (GICON).

(Image above: Dr. Martin Ecke, GICON)

“The spiral arrangement of the fir tree shape has the advantage of making better use of the light incidence compared to linearly arranged rows of tubes,” explains Ecke, departmental engineer at GICON. A constant problem in land-based microalgae cultivation, namely excessive heat production due to the energy generated during photosynthesis, is solved in a simple yet ingenious way in the fir tree: The plastic spiral is a double-walled tube through which a second circuit of cooling water flows. Even a few degrees difference can have a major effect on algae. This system may also make it possible to maintain the productivity of the plant during the winter months.

In the next project step, the microalgae reactor will be installed and commissioned on the premises of the B.E.S. biogas plant in Bad Bentheim. It remains to be seen how good the cleaning performance will actually be and what exactly the by-products will be. The project will run until the end of 2024.