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What Are Microalgae?

The term algae represent a large group of plant-like organisms with sub-division classifications. The prefix micro refers to their size compared to similar organisms. The three major classifications are microalgae, macroalgae and cyanobacteria. These organisms can exist as either unicellular, multicellular, filamentous, or colonial structures. Microalgae can convert solar energy into chemical energy by fixing atmospheric CO2. 

Everyone at some point has come into contact with microalgae. Whether at a lake/pond, to a shaded region of the garden to a fish tank. Chances are, even if you have been living under a rock, you would have met microalgae. This versatility of microalgae to live in almost every habitat in the world is what makes these tiny green power-house such a remarkable species. 

Without getting too technical, microalgae can be classed as either eukaryotic or prokaryotic. They play a fundamental role within the world’s food chain. By consuming waste material, converting fundamental elements into a wide range of compounds for larger predators to thrive, these creatures are at the core of sustaining life on Earth. 

Different species of microalgae

Whats so Special About Them?

Microalgae have this unique ability to synthesise their own food, like plants do, with the exception that they behave like animal cells. That is why we can often think of microalgae as being both a plant and an animal. In a nutshell, they behave and operate like plant cells, but resemble animal cell structures. 

These tiny creatures, while small in size, pack a serious punch. The range of biochemical compounds produced by microalgae is immense. What’s more incredible is the potential applications these compounds can be used for. More on that later on. 

Microalgae are so widespread across the world, that they have adapted to almost any environment on the planet. It’s no wonder there are over 100,000 confirmed species, however, some researchers believe there could be as many as 800,000 different species! 

It’s not just the wide range of different species that makes them so special, it’s also the wide range of biochemical compounds they produce. This is the exciting part of how microalgae have the potential to revolutionise several industries, simply down to the compounds they produce. We will talk about this in more detail.

Microalgae cultivation process

What Biochemical Compounds Do They Produce?

The short answer here is… A lot! Microalgae produce a plethora of different biochemical compounds that can be used in several different industries. Most suitably the pharmaceutical and nutraceutical industries. 

While microalgae get a lot of attention for their use in biofuel production, their other high-value compounds are where the real magic happens. The shift to a more naturally sourced product, for instance in skin care makes the products from microalgae highly lucrative since everything they produce is natural and sustainable. 

A good example of a compound is one called lutien. Some species of microalgae produce a specific type of lutien that is found in the human eye, and without this compound our eyes would vapourise when exposed to oxygen. The compounds is very expensive and hard to obtain in large quantities naturally, however, microalgae produce this compound in spades! 

Further examples of compounds microalgae produce are things such as carotenoids (dyes), polyphenols, vitamins, proteins, carbohydrates, lutein, and much much more. Granted the quantity of these specialised compounds is low, however, the manufacturing process is completely organic and 100% sustainable! 

So microalgae as you can see is so much more than just biofuel. To unlock their full potential, the design of a biorefinery needs to be developed. Just like a traditional petroleum refinery, a biorefinery would see the extraction of multiple compounds from the same batch of algae. This would significantly improve the economic performance of microalgae, and make it a huge contented for several markets. 

Microalgae biochemical compounds

Do They Produce Biofuel?

Not directly, no. This is a misconception when it comes to microalgae and biofuel production. Microalgae produce what are known as lipids. These are fats that can be converted into biofuel/biodiesel through a process known as transesterification. Without going into the depths of the chemistry, the general process for conversion is as follows… 

The name of the process can be broken down into “trans” and “ester”. The term “trans” suggests the change/transfer of reactants to products. The term “ester” refers to the type of molecule being produced. 

For all the budding chemists, an ester is formed by reacting an alcohol with a fat or oil, in the presence of a catalyst to speed up the rate of the reaction. So you guessed it to make biofuel, we use the lipids produced from the algae. We simply take the lipids and react them with a low carbon chain alcohol; usually methanol or ethanol. 

It’s very important to remember that the presence of water within an internal combustion engine can cause critical damage and reduce the performance of combustible fuel. Therefore it is crucial to ensure the lipids extracted from microalgae are completely dry. 

Microalgae biofuel production

Whats The Limitations?

There’s always a catch isn’t there? While everything so far has been positive about microalgae, and while my research is looking deep into the extraction of these high-value compounds, I am in no way biased towards microalgae and know there are significant bottlenecks that must be overcome, before this technology can rival the oil and gas giants, as well as many other big businesses. 

It all comes down to two things: economics and volume. The problem we face just now is that the quantity of these compounds produced per gram of algae, isn’t enough the meet the demand and to compete with other big businesses, therefore there is essentially a limit as to what can be harvested at any one batch.

The second issue being the economics, and this is a direct consequence of the volume of recovered compounds. While a lot of the compounds have pharmaceutical applications, which inherently comes with a big price tag, the cost of extraction is just too high. This is on the basis we consider extracting one compound per batch. This is where the idea of the biorefinery comes into play. By extracting multiple compounds simultaneously, we instantly improve the economic performance of each gram of algae, which results in a more competitive end product. 

Another limitation currently is the level of funding by government and privet sector investors. Up until the last few years, microalgae have always seemed insignificant and dwarfed by other renewable energy sources such as wind, solar, and tidal. Having access to more funding would propel the advancements by several years as with better equipment being developed, new ideas being explored, the potential is there, we just need to finances to unlock them! 

Microalgae cultivation technology

Whats The Future For Microalgae?

Dare I say the future is looking green? I truly believe the future of microalgae is looking great. Do I think it will be within the biofuel industry… probably not? However, I do believe biofuel will play an important role in the overall success of microalgae. 

The future will indeed lie with the development of the biorefinery, combined with hybrid and less energy-intensive extraction and purification processes. 

For us a species to survive we relied on microalgae filling the atmosphere with oxygen, we relied on microalgae being the primary food source at the beginning of the food chain, and we will rely on microalgae being the key to our energy and environmental crisis solution. 

This highly diverse, adaptable, amazing species really packs a punch requiring very little to produce so much in return. The future is looking bright for microalgae and I am confident in the future people will fully appreciate the enormous benefits microalgae can supply us with!