Algoliner is revolutionizing microalgae cultivation with the help of ACRYLITE® molding compounds and a mobile factory

• Algoliner develops pioneering technology for fast, cost-efficient and resource-saving construction of photobioreactors
• Tubes made from ACRYLITE® molding compounds in a mobile factory reduce the environmental footprint of algae reactors
• Brand PMMA’s transparency allows highly efficient production of sustainable biomass

A truck pulls up. It is carrying a mobile factory in which long, transparent tubes made from a ACRYLITE® molding compound are extruded. They run off the truck on rails, ready for installation, and are attached to supports with a few simple steps. The microalgae farm is ready. The German company Algoliner has revolutionized the construction of algae reactors with this innovative process and Röhm’s brand polymethyl methacrylate (PMMA) in the Americas.

“Our mobile extrusion system allows us to install closed photobioreactors rapidly almost anywhere, at low cost and while saving resources,” says Hans Väth, Founder and Managing Partner at Algoliner. “We use the molding compound ACRYLITE® 7H to produce tubes in all required lengths. The material is so light that even tubes 100 meters in length can be positioned by a single person.”

Microalgae: the raw material of the future

Microalgae are considered one of the most important raw materials of the future. Cultivating these fast-growing organisms makes it possible to generate enormous quantities of biomass, without competing for agricultural space. All the microscopic organisms need to grow is sunlight, carbon dioxide and a little water. A high-quality protein source for food and animal feed, they also contain active ingredients for pharmaceuticals and the chemical industry. Algae biomass can also be used to generate energy or raw materials for producing bioplastics. ACRYLITE® is thus contributing to climate-friendly technologies.

Mobile factory saves resources

Fascinated by this enormous potential, Väth has been looking at microalgae for a long time now. Having analyzed common types of algae reactors, he found that it is more sustainable to extrude standardized plastic tubes in the required length directly on site, rather than sending heavy glass tubes halfway around the world in crates before joining them together in a complex process. “A mobile factory thus saves energy, CO2 and of course labor.”

ACRYLITE® offers myriad advantages for algae reactors

Väth did not have to look long to find a suitable plastic. “My thinking was, either our system works with PMMA – or we don’t do it,” says the Managing Partner, who holds a degree in engineering, specializing in plastics technology. Explaining his reasons for choosing the material, he continues: “ACRYLITE® impresses with its extraordinary transparency, which is crucial for algae growth. In addition, it is a sustainable material with a very long lifespan, and can even be fully recycled at the end of its useful life.”

Because Algoliner has developed a patented hanging system – in which the tubes are hung between supports and given a special profile to allow them to be attached in this way – the company has succeeded in reducing the wall thickness to just one millimeter and the tube weight to 250 grams per meter.

In experiments, Väth and his team were able to disprove the concerns of skeptics regarding PMMA’s heat expansion and the possibility of cracks forming on the flanges. The ACRYLITE® tube profiles proved both stable and elastic enough to compensate any uneven areas and slight vibrations. “They can be moved almost like a hose,” describes Väth. Thanks to their shape, the profiles are rigid where necessary. The system therefore needs fewer support elements than conventional photobioreactor designs.

ACRYLITE® 7H especially for extrusion

The tubes are extruded from ACRYLITE® 7H molding compound and the flanges injection-molded from ACRYLITE® 8N. The two elements are joined together with ACRIFIX® from Röhm, a special polymerization adhesive based on MMA/PMMA. “With its excellent melt viscosity and heat deflection temperature, ACRYLITE® 7H offers a balanced profile of properties for the extrusion of tubes and technical profiles,” says Heinz Schubkegel, Senior Business Manager in the Molding Compounds business unit at Röhm GmbH. “Like all the transparent ACRYLITE® molding compounds, it has unparalleled transparency of up to 92 percent. And thanks to its excellent UV and weather resistance, it retains its transparency even outdoors, without yellowing.” This provides the ideal conditions for the light-hungry algae, allowing a very long useful life for the reactors at the same time.

Research project “smartPBR”

Some parts of the world, however, have a shortage of sunlight. In regions such as Iceland, with its long, dark winter months, natural light is not sufficient for even algae growth. Excess algae growth is also a problem, since the more biomass is generated, the denser and darker it becomes inside the tubes. Controllable artificial light is therefore used to help encourage or slow down algae growth in a targeted way.

Together with the Laboratory of Adaptive Lighting Systems and Visual Processing at the Technical University of Darmstadt, Germany, Algoliner is currently working on an AI-based lighting concept for photobioreactors. The Federal Ministry for Economic Affairs and Climate Action is supporting the “smartPBR” research project as part of its Central Innovation Programme for SMEs (ZIM). “A self-learning system ensures that all parameters work together in the best possible way, so that electric light can be used as an additional light source,” explains Väth, “for example depending on the weather or when electricity is available at low cost.”

Algoliner’s patented hanging profile has a second function here, serving as a channel for LED strings. This allows lighting to be integrated into the system efficiently: A third of the beams of light are directed straight down into the tube, while one third helps to light each of the neighboring tubes. “Our type of light guidance is 30 to 50 percent more effective than the usual side lighting, which loses a great deal to scatter,” says Väth. The maximum transparency of the ACRYLITE® tubes makes a significant contribution to the lighting’s efficiency – and thus to a high microalgae yield.

Producing a sustainable raw material even more sustainably

As a company, Algoliner sets itself the standard of reducing the environmental footprint of biophotoreactors with low energy and material consumption and environmentally friendly, recyclable materials. “ACRYLITE® is the most sustainable solution,” says Väth with conviction. He is currently working on a life cycle analysis (LCA) to prove it.

With all components of the algae reactor made from ACRYLITE® molding compounds, they could all be ground down together at the end of the system’s life cycle. This ground material can then be fully reused, either by being broken down into its original chemical constituents or directly in thermoplastic processes. “The sustainable product design thus significantly enhances the recyclability, as no foreign plastics have to be laboriously separated out before the recycling process,” says Sven Schröbel, Head of Global Sustainability Management at Röhm GmbH’s Molding Compounds business unit. Already, production waste from tube extrusion at Algoliner is being reprocessed directly into flanges using thermoplastic processes, thus remaining in circulation. “The Algoliner concept is an excellent example of how ingenious product design and the choice of long-lasting ACRYLITE® materials can make the final product significantly more sustainable – sustainable by design,” Schröbel continues.

Special flanges guarantee hygiene

The connections between the tubes are problem zones in conventional bioreactors, as deposits form in the gaps – fertile ground for germs that can contaminate the biomass. Algoliner has succeeded in using ACRYLITE® molding compound to produce transparent flanges whose seal is injected in such a way that it bulges inwards, so that no dead flow areas arise. This largely prevents contamination. Another benefit in terms of hygiene is PMMA’s completely smooth surface, which makes it difficult for biofilm to form in the tubes. Despite this, the system needs constant cleaning when used to grow microalgae for food production. Ball-shaped brushes move through the inside of the tubes, leaving them totally undamaged thanks to the high surface hardness and scratch resistance of ACRYLITE®.

Microalgae: a beacon of hope for agriculture

Algoliner is continuously advancing this technology in multiple research projects. “We receive inquiries from all over the world,” says Managing Partner Väth. “From Australia, for example, where water shortages make agriculture difficult, and from India, where there is interest in producing a lot of biomass on a small area. And the Swiss Federal Office for Agriculture is using an Algoliner reactor to conduct research into the option of reducing methane emissions in cattle farming by adding microalgae to feed.” The tiny organisms have enormous potential to meet some of the major challenges of the future.