4/4 Spirulina 101: The Barriers

Klara Zietlow
6 min readNov 28, 2021


You’ve made it to the end! This is the last article in a series on everything you need to know about spirulina. If you have no idea what I’m talking about, here’s article one, the introduction, article two, different ways to grow and harvest spirulina, and article three, spirulina’s nutrition & applications.

Get ready to learn all the terribly sad, tragic reasons why these little guys aren’t taking over the world (yet)

Cost 💸

Cost is probably the biggest barrier, since spirulina hasn’t been grown on a mass scale for very long.

It’s potential to be super cheap due to the idea that “free light plus free carbon dioxide equals valuable protein” means it has gotten a lot of research. But, the low cost of carbon and energy it needs is offset by other, more expensive factors.

Instead of just getting seeds and digging holes in the ground, spirulina requires that one build up infrastructure to not only grow but also process the product.

Since cyanobacteria depend on photosynthesis, the layer of nutrient medium in which the cells grow must be relatively thin or most of it will not be photosynthesizing. This means that although microalgal culture isn’t as land intensive as agriculture, it still isn’t able to just condense into one big fat bioreactor like cellular agriculture or bacterial protein can.

Some companies use narrow glass tubes as their bioreactor of choice. This certainly comes with the benefit of high light penetration but I was skeptical about how easy it is to clean them.

Woooooooooow I Kurier

I was surprised to learn they’re actually supposed to be quite easy to clean! This is due to the smooth, resistant surface of glass, though it’s probably not as easy to clean as a Raceway. It’s good to hear that it’s totally doable though and should definitely be explored further.

Evaporation 🌞

If natural light, the cheaper option, were to be used, many parts of the world with enough sun would have too much evaporation. This means that a cheap water source would need to be found, perhaps wastewater, and then tested for safety.

Deserts are great to use for spirulina…except for evaporation I DIC

Nutrients 🍝

15–25% of spirulina biomass production cost goes towards nutrients.

There have been few studies that explore the avenue of reusing culture medium but if achieved, this would lead to significant savings reducing water demand by 84%.

The most commonly used medium, Zarrouk medium, costs $0.08 per liter. Alternatives have been developed based on the Zarrouk medium including one just as effective yet 5x less expensive. More research should be done on optimizing nutrients for cost and performance.

Energy ⚡

Around 5.5% of the cost of growing spirulina in a Raceway goes towards energy and this percentage only rises with closed bioreactors.

This can be increased or decreased dramatically based on the equipment used during post processing but is still significant. It’s also not as simple as choosing the least energy intensive method: often there’s a trade off between energy usage and efficiency. A drum dryer, for example, uses much less energy than a spray dryer but it takes more space since it’s not as effective.

Strain Selection 🔬

The main factors spirulina strains are selected for include growth rate, biochemical composition (for nutrition or function), and resistance to environmental stress.

Desired traits can be achieved via selective breeding but a quicker way to get the exact desired effects is genetic engineering. Alas, gene edited products are harder to market and even a strain showing good performance in the lab may not perform the same way in a bioreactor.

🧫🧬🧪👩‍🔬 I Genetic Literacy Project

Even once a good strain is found and cultivated in the bioreactor, it’s likely to mutate which could make growing or harvesting it more difficult. For example, the strain I got from a farm to grow at home mutated to become super large. As a result, it requires a lot more sunlight than regularly sized coils and doesn’t do too well in Winter.

The ginormous coils from the farm compared to the spirulina I bought from Algae Research Supply

Nutrition and Safety 🦺

There aren’t many nutritional issues that have been reported from spirulina and those that have are often due to an unreliable source. Because spirulina can soak up heavy metals and other contaminants in its medium, if it’s grown in an unclean environment these toxins can get passed onto the person who consumes it.

Still, all microalgae contain high protein and chlorophyll content which at excess can cause gastrointestinal issues such as diarrhea, nausea, or cramps. High levels of phosphorus of which excessive intake can have deleterious effects on the kidneys. If you already have high levels of iron, eating spirulina could give you gastrointestinal distress. Too much manganese can even lead to neurotoxic effects.

But, these are in huge amounts. I find it funny that the health complications that come with spirulina are from too many nutrients. 😂

Awareness of the side effects is important, but a bit of spirulina everyday will definitely help a lot more than it will hurt you.

Shelf Life 🛒

Vitamins in spirulina are destroyed under heat processing which includes spray drying, microwave and oven drying. This is the same for antioxidants and phytonutrients present in spirulina.

As a result, fresh spirulina is much better for your health, not to mention it has a much more neutral taste.

Greenspring Farms’ fresh spirulina (Super nice people + high quality spirulina!)

The drawback is that fresh spirulina is so much more prone to spoilage; a couple of weeks instead of 10+ years like dry spirulina.


The knowledge we have about spirulina has come a long way since it was first spotted on a pond many hundreds of years ago. We now have dozens of different ways to harvest it, hundreds of scientific papers, and thousands of recipes and ways to use it circling the internet.

Although it’s one of the oldest life forms on Earth, we’re just beginning to realize its potential. Who knows what other amazing things we’ll discover about spirulina.

With this 4-part series I hope you gained a deeper understanding of what spirulina is, why it’s important, and the work that still needs to be done.

If you’re interested in growing your own spirulina, Spirulina Society has a great tutorial. Or, if you’d rather just buy it, I encourage you to support Greenspring Farms because they have really high quality spirulina and helped me out a lot when I first started growing spirulina myself. ❤

Thank you so much for sticking with me to the end! I hope you learned a lot about spirulina and are now eager to do some research of your own!

If you haven’t read the other articles in the series, check them out!

  1. The Introduction
  2. Methods of Growing and Harvesting Spirulina
  3. Nutrition and Uses for Spirulina

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Klara Zietlow

Passionate about the future of food and the environment. Likes animals too :)