Fish farms, for example, use a huge amount of fishmeal and fish oil to feed all their fish. It takes on average two kilos of food, which is largely made up of fish and sea animals caught in the ocean, to produce one kilo of edible farmed fish. That’s not sustainable. But there’s an alternative.
Instead of serving ground fish from the open sea, we can also feed farmed fish with algae-based fish food, which is the basic food in most aquatic ecosystems. Algae – a group name for thousands of uni- and multi-cellular organisms that perform photosynthesis – contain many unsaturated fatty acids (like omega-3 and omega-6), antioxidants, some essential amino acids and other substances that we humans associate with a healthy diet.
What’s more, algae, as a whole or after processing, can be used in food products for humans, in cosmetics, in health additives, in animal feed and in industrial chemistry.
To show to industry that cultivating algae – called algaculture – is a promising and economically viable method of moving towards a bio-based and sustainable economy, the Flemish Institute for Technological Research (Vito) and the University College Thomas More Kempen are building a large pilot installation, known as Sunbuilt, at the Thomas More campus in Geel. The photobioreactor (PBR), a machine in which algae can grow thanks to sunlight and water while producing oxygen and biomass, is due to start working in the autumn of next year.
So how are algae cultivated? “You have several options,” explains Bert Lemmens of Vito. “You can cultivate them in large open ponds of shallow water, with a paddle wheel that moves the water around. Those ponds are placed inside greenhouses, which opens up new opportunities for Flemish horticulture.”
Other options, he says, are cultivating them inside PBRs, consisting of tubes, flat panels or plastic bags. “The appropriate method depends on the type of algae and the desired end product.”
Only a limited number of algae can be produced in open ponds. That’s why a photobioreactor was chosen for this project. In the PBR, the quality of the algae can be regulated more effectively. Algae are very sensitive to changes in temperature or light, leading to a different quality of algae. So for this pilot installation, a PBR was a logical choice.
The production scale of the Sunbuilt algae plant lies between the laboratory and industrial level. “Sunbuilt will yield up to 500 kilos of algae, in dry powder, per year,” says Lemmens. “That’s enough to perform daily tests concerning the quality and the applicability of the algae powder.” Vito’s role in the project is in the harvesting and processing technology.
“Sunbuilt is a good example of a symbiotic relationship,” says Lemmens. “Our strength is our experience in separation and bio-refinery techniques. Our partner, Thomas More Kempen, has expertise in greenhouse cultivation, which has many similarities with algae production.”
Algaculture is also an opportunity to reinforce Flemish industry in many different fields. Horticulture, a sector that has been suffering for some time from competition from producers in other countries, will have a new crop with high added value. The food industry will have new ingredients. The chemical industry will have sustainable resources.
“Also, we could replace part of the soy that is used in animal feed and comes from countries like Brazil with algae,” says Lemmens. “This would contribute to a more sustainable agriculture in Flanders and reduce the excess production of manure. The applications range, then, from extremely high to low added-value products.”
The world of algae yields a huge richness of diversity, with an estimated 200,000 to 800,000 sorts. Of these species, only 50,000 have been described by science and less than 100 have been produced at laboratory scale. There is, therefore, still an enormous potential for new crops and products that is still undeveloped.