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  • New Zealand Algae Innovations Ltd currently operates the only spirulina farm in New Zealand. Under the brand name Tahi Spirulina, it sells a range of spirulina food and supplement products.

    Background

    Biotechnologist and engineer Professor Benoit Guieysse has focused his research on industrial applications for algae. Benoit has investigated microalgae (microscopic algae) as a fossil fuel alternative and for wastewater treatment.

    Not convinced from his modelling that high production of a microalgae-based alternative fuel could be environmentally friendly, Benoit explored other commercial possibilities for growing microalgae in New Zealand. The temperate New Zealand climate is ideal for microalgae cultivation, with nearly 10 out of 12 months of the year providing good growing conditions.

    In France while visiting a research facility, Benoit’s interest turned to spirulina. He enquired about a small dryer and was surprised to discover it was being made for a local spirulina farm — and that there were more than a hundred spirulina farms in France.

    Spirulina – what is it?

    Spirulina is a ‘superfood’ rich in iron, antioxidants and B vitamins as well as vital minerals including magnesium, phosphorus, calcium and zinc. One heaped teaspoon of spirulina powder delivers 6 milligrams of natural iron, which is over 50% of the average adult’s recommended daily intake. Spirulina is also rich in complete protein, and the conditions for growing it make it a sustainable protein option. The Food and Agriculture Organization reports that spirulina provides 200 times more protein per hectare than beef.

    Scientifically, spirulina is classified as cyanobacteria. Cyanobacteria are a type of photosynthetic bacteria. They are prokaryotic and belong to the monera kingdom.

    Spirulina is often called a microalgae. However, microalgae belong to the protist kingdom. Protists are any eukaryotic organism that is not an animal, plant or fungus.

    Common names can create further confusion – the common name for cyanobacteria is blue-green algae. They are often lumped together as they occupy similar environments.

    Nature of science

    Over time, as knowledge and understanding develops, so does the classification of living organisms. The classification of cyanobacteria is an example of this. Prior to 1866, bacteria were classified as plants and a number of cyanobacteria were classified as algae. Cyanobacteria have some characteristics of both plants and algae. They produce their own food through photosynthesis – the difference is that cyanobacteria do not have a nuclear membrane nor membrane-bound organelles. They are prokaryotic and algae and plants are eukaryotic.

    Spirulina (Arthrospira platensis) is a filamentous cyanobacteria. There are at least two species that are used for commercial cultivation.

    Growing spirulina

    The artisan production model developed in France was the catalyst for Benoit to form a company with others to investigate and pilot the first spirulina farm in New Zealand – New Zealand Algae Innovations Ltd.

    The French artisan method utilises covered ponds and dries the spirulina at low temperatures to assure a clean and nutritionally dense end product. Standard commercial production seen in large-scale operations in China, India and the USA use very large open ponds and spray dryers (the same technique is used to produce milk powder). The open cultivation system can result in contamination from birds and other materials and high water evaporation into the environment, and the spray dryers operate at temperatures that can reduce the nutritional profile of the end product.

    The company set up spirulina cultivation at Himatangi Beach in Manawatū. A starter culture was imported. Meeting food safety and cultivation regulatory requirements was a challenge for this ‘novel food’ that bridges the horticulture and aquaculture industries. Import permissions were aided by evidence in a 1960s academic paper that showed the strain of cyanobacteria that was being imported was already present in New Zealand.

    Within a few years, the company had gone through a number of iterations of its custom-built ponds and processing system as it refined the operation. Presently, it operates two shallow raceway ponds under greenhouses. Drying, grinding and packaging of the Tahi Spirulina powder are done on site.

    The key to growing spirulina is water, CO₂ and sunlight. Spirulina cyanobacteria produces its own food by photosynthesis, supplementing this with minerals from the water. Tahi Spirulina adds minerals to the water, being careful to avoid certain additives that could contaminate the flavour such as fish-based products. A paddle system keeps the ponds mixed, and the greenhouse covering reduces water evaporation while assuring environmental contaminants are kept out.

    Spirulina is fast growing and can be harvested in 2–3 weeks. Harvesting is a manual operation that starts with pumping the water and spirulina through a vibrating filter to separate out the spirulina slurry from the water. Water is returned to the ponds. The slurry is pressed further until it resembles a ‘playdough’ texture. Using an adapted sausage extruder, the ‘dough’ is extruded into long noodles for drying.

    The dried noodles (the shape of whole unground spirulina) are then broken up to produce Tahi Spirulina Crunchies and finely ground to produce the powder.

    Ongoing research and scale-up

    Presently, New Zealand Algae Innovations is selling all its product, so increasing capacity will be important for the company to grow. The company is investigating the viability of moving from the present 400 m² production unit to a commercial pilot of 6,000 m². Scale-up increases production and it is also important for resilience. More ponds mean the company can weather the collapse of microalgae cultures that can occasionally occur and cause issues for production and supply.

    The main focus remains on spirulina, but the company will eventually look to investigate microalgae species for applications such as food industry pigments and cosmetics.

    Related content

    Spirulina is a nutrient-rich food. Learn about the macronutrients and micronutrients humans require for good health.

    See our Seaweed and algae Pinterest board for more resource ideas.

    Useful links

    Take a look at some of the Tahi spirulina products and the marketing story. There’s also a number of recipes that could be a starting point to inspire some innovative food technologists!

    Tahi Spirulina has been working with the Pūhoro Stem Academy – read about how it’s inspiring the next generation of food scientists and technologists in Pūhoro produces results for young Māori interns.

    The Food and Agricultural Organization has produced a report on farming spirulina. The report compares spirulina protein yields with other protein-rich food.

    Acknowledgement

    The resource is adapted from the article by Rural Delivery, a television programme that looks at excellence and innovation within the primary industries in New Zealand. The Science Learning Hub acknowledges Showdown Productions for the use of this article and the accompanying video clip.

      Published 27 September 2022 Referencing Hub articles
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