Applications

The biotechnology of microalgae has gained considerable importance in recent decades. Applications range from production for food supplements, animal feed and live feed in aquaculture to valuable products for pharmaceutical and ecological applications. Also exploitation of microalgae for bioenergy generation or combined applications for biofuels and CO₂-mitigation, by which CO₂ is captured and sequestered, are under research. For most of the applications, the market is still developing and the biotechnological use of microalgae will extend into new areas. Considering the enormous biodiversity of microalgae and developments in genetic engineering, this group of organisms represents one of the most promising sources for new products and applications.

Human nutrition

Microalgae have positive effect on the health of humans. The high protein content is one of the main reasons to consider them as an unconventional source of protein. Also microalgae are the origin of polyunsaturated fatty acids (PUFAs of more than 18 carbons).

Animal nutrition

More than 40 different species of microalgae are used in fish and shellfish farming (aquaculture). They are the natural food for these animals. Representing a good source of protein, pigments and PUFAs they are also used as feed for pets and farm animals.

Cosmetics

Microalgae extracts are added to skin care products (tissue regeneration, wrinkle reduction), hair products…

High value molecules

Microalgae are the source of PUFAs, pigments and stable isotope biochemicals.

Wastewater treatment

In the process of wastewater treatment microalgae can be directly used to remove nitrate and phosphate ions. The microalgal biomass is expanded due to these ions, which are utilized as nutrients. Further the biomass can be used to gain energy for example in the biogas plant. Also microalgae can be used to treat waters where bacteria are not successful.

Indirectly microalgae can be used in combination with bacteria. They provide oxygen to aerobic bacteria to mineralize organic pollutants and use the CO₂ released by bacteria. Mechanical aeration accounts for more than 50% of the total energy consumption of typical (bacterial) aerobic wastewater treatment. The mixing is especially not wanted when handling hazardous materials. The aerosols or hazardous materials are by mixing released in the air.

Biofertilizers

Microalgae produce polymers that influence water storage and particle adherence in soils. Maybe one of the first biotechnology applications of microalgae is due to nitrogen-fixing ability of cyanobacteria their use in fertilizing rice fields. Today it is known that some microalge produce bioactive components that influence higher plants to be more resistant to plant diseases.

Energy

Microalgae can be used to produce biogas, bioethanol and biodiesel. For example the biomass gained in the process of wastewater treatment can be used in biogas plant to produce electrical power. The components of cell wall and storage sugars can be used to produce bioethanol and the lipids can be used to produce biodiesel.

CO₂ mitigation and sequestration

The worldwide awareness about global warming as a result of the rising levels of different greenhouse gases such as CO₂ released from the burning of fossil fuels have resulted in proposing different methods for CO₂ mitigation and sequestration. To use of microalgae to fix CO₂ released from power plants via the exhaust gas or to permanently fix CO₂ (immobilize) and put it in long-term storage are both promising ideas.