For a few years now, research and experimentation has been carried out with microalgae for use in the manufacture of biofuels. These investigations are based on the fact that microalgae have several advantages over other traditional raw materials, such as plant crops or agricultural waste. Currently, these microalgae are used for various purposes, such as in the pharmaceutical or food industry, but their potential as an energy source seems to be very promising.
Microalgae are photoautotrophic unicellular microorganisms that have the ability to generate energy through photosynthesis and synthesize their biomolecules from simple compounds such as water y carbon dioxide (CO2)This makes microalgae a key tool not only for the production of biofuels, but also for the reduction of greenhouse gases, since they absorb CO2 during their growth.
What are microalgae and how do they work?
Microalgae are unicellular photosynthetic organisms present in a wide variety of aquatic environments. Around 30.000 species are known, although only 50 have been studied in depth and less than 10% are used commercially. This leaves a huge scope for research to find species with efficient characteristics for biofuel production.
Furthermore, microalgae have an extremely fast growth cycle. While land plants can take months to develop, some microalgae species can double their mass in a matter of hours. This provides a competitive advantage when it comes to producing large amounts of biomass in small spaces and in a shorter time, which in turn increases the profitability of their use.
Advantages of microalgae in biofuel production
- Abundance and diversity on the planet: Microalgae are highly abundant and diverse. Their ability to adapt to different types of environments, both aquatic and terrestrial, gives them great flexibility for cultivation in various conditions. In addition, their wide range of species allows the selection of those most suitable for each type of biofuel.
- Top performance: Microalgae are much more productive in terms of biomass than conventional crops used for biofuels, such as corn or soybeans. They produce up to 100 times more biomass per unit area, which translates into a greater amount of biofuel per hectare.
- They do not compete with food crops: Unlike other plant-based sources of biofuels, microalgae do not require fertile farmland to grow. They can be grown in wastewater, saline waters or even on land unsuitable for agriculture, minimising the impact on food security.
- Use of CO2 and lower environmental impact: Microalgae consume large amounts of CO2 during their growth. This not only benefits the photosynthesis process, but also helps reduce the concentration of this gas in the atmosphere, contributing to the fight against climate change.
- Production of multiple compounds: Microalgae are capable of producing lipids for biodiesel, carbohydrates for bioethanol and proteins that can be used as food or supplements. Secondary products with applications in the pharmaceutical and cosmetic industries can also be obtained from their biomass.
Biofuel production from microalgae
There are different types of biofuels that can be produced from microalgae, each with particular characteristics that make them ideal for different types of uses. Among the most common biofuels are: biodiesel, the bioethanol, the biogas and the biohydrogenEach of these fuels is obtained from different components of microalgae, such as lipids and carbohydrates.
Biodiesel from microalgae
El biodiesel It is one of the best-known biofuels and is obtained mainly from the lipids (fats) stored inside microalgae. To produce it, lipids are extracted from the algae cells and then subjected to a chemical process known as transesterification, which converts them into methyl esters, the main component of biodiesel.
The extraction process is expensive, but research into new lipid extraction techniques and the development of fatty acid-enriched microalgae is advancing rapidly. In addition, certain advances in the treatment of algal biomass to produce biofuel have allowed greater efficiency in obtaining biodiesel, mainly through techniques such as hydrothermal liquefaction (HTL), which treats wet biomass at high pressure and temperature.
Bioethanol from microalgae
El bioethanol It is obtained through the fermentation of carbohydrates stored in microalgae. After pre-treatment of the biomass to separate the sugars, yeasts and bacteria are used to convert these carbohydrates into ethanol. Although the process is similar to that used for corn or sugar cane, microalgae have the advantage of not requiring large areas of land or fertilizers, and they do not compete with crops intended for human consumption.
Biogas from microalgae
El biogas Biogas is another biofuel that can be produced using microalgae. Through a process of anaerobic digestion, the carbohydrates and lipids present in algae are broken down in the absence of oxygen to generate methane and carbon dioxide. This biogas can be used in the same way as natural gas, allowing the generation of electricity or use in heating systems.
Biofuels in industry and transport
In addition to electricity production from biogas, biofuels derived from microalgae have key applications in sectors such as transport and aviation. Currently, biodiesel produced from microalgae is being investigated as a viable alternative for fuels in commercial aviation, which is one of the most difficult sectors to decarbonise. biokerosene derived from microalgae could be a viable solution to reduce CO2 emissions in this sector.
Applications are also being studied in the biopolymer production, which are biodegradable plastics generated from by-products such as glycerol obtained during the lipid transesterification process. This could add additional economic value to microalgae production, making them more competitive compared to other raw materials used for biofuels.
Production costs remain the main obstacle to mass commercialization of microalgae-based biofuels, but scientific and technological advances suggest a promising future for this industry. As the efficiency of the cultivation and extraction process improves, and biofuel refining technologies are further developed, there is no doubt that microalgae will position themselves as one of the main sources of renewable energy in the world.
In short, microalgae not only hold promise for biofuel production, but also offer a sustainable solution to mitigate the energy and environmental problems of our society. Their ability to adapt to different environments, their high production performance and their potential to absorb CO2 make microalgae an excellent option in the search for clean and viable energy alternatives.