Microalgae produce valuable biomass more efficiently than any land plant. And because these little all-rounders primarily require plenty of even light to do their job, the algae grower Algicel relies on transparent tubes made of PLEXIGLAS®.
In dietary supplements, cosmetics, pharmaceutical products and even in energy generation: microalgae can already be used in a variety of ways. However, researchers are constantly discovering new application options for these little miracle plants.
The founders of the Portuguese company Algicel discovered a high concentration of the antioxidant astaxanthin in the microalgae in their native Azores, more precisely on the island of São Miguel. Antioxidants protect not only the skin’s cell structure, but also the whole body against oxidative stress and aging symptoms as well as inflammation.
Since 2007, the company has been researching a way to produce the health-promoting substance astaxanthin from the microalgae growing in their natural environment on the Azores. After all, the climate and pure inland waters of the islands are ideal for this type of microalgae. In the summer of 2019, the company started the industrial cultivation of the Haematococcus pluvialis species of microalgae on the basis of technology that was developed in-house.
Optimum growth conditions
In order to produce the microalgae for the mass market, the company first had to create an environment which is similar to that of the inland water bodies of the Azores. Algicel opted for so-called photobioreactors made of PLEXIGLAS® XT tubes. This version of the brand acrylic glass is UV permeable across the entire spectrum of sun rays and, together with the 92-percent transparency, provides optimum conditions for the microalgae. Along with nutrients, water and carbon dioxide from the air, algae primarily require plenty of even light for growing.
Cultivation under laboratory conditions
The prototype of the company’s microalgae is similar to the Azorean type and was developed by the founders of Algicel and the Universidade dos Açores. This special type is especially robust, nutrient-rich and thus ideally suited for use in dietary supplements and cosmetics. In the summer of 2019, Algicel started the industrial cultivation of the special microalgae under controlled conditions in a hall.
The PLEXIGLAS® tubes do not have any irregularities or grooves on the inside, meaning that during growth, no algae deposits accumulate on the surface. Alongside cultivation under controlled conditions indoors, the algae are also to be cultivated outdoors.
“PLEXIGLAS® is one of the most transparent materials available today. There is virtually no absorption of visible light in the material,” says Janina Rossmann, Product Manager for PLEXIGLAS® tubes at the company manufacturing the brand acrylic glass. And, the transparency of the tubes remains unchanged for decades: PLEXIGLAS® has UV protection inherent to the material. This prevents yellowing and thus the loss of transparency in virtually all colorless, transparent versions of the brand acrylic glass – guaranteed for 30 years.
Rapid plant growth
Thanks to these properties, the microalgae now grow under nearly natural conditions and reach their maximum number within just 30 days. Harvesting takes place by centrifugation of the mix – water/microalgae. “The absolute roundness of our tubes means that there are no edges that could cause trouble,” Rossmann explains.
Then, the harvest cycle begins again. The more than 1,000 two-meter-high tubes have to be rinsed and refilled with every cycle. The smooth, non-porous inner walls ensure that no putrid bacteria or microorganisms remain stuck to the walls. This keeps the PLEXIGLAS® tubes clean during the entire cultivation – thereby contributing to an efficient and sustainable biomass production.