The microalga Nannochloropsis oceanica shows promise as a sustainable source of important nutrients like protein, omega-3 fatty acids, and vitamin K2. Recent research indicates that factors such as temperature and light significantly influence nutrient yield.
As the search for sustainable food production methods continues, microalgae are emerging as a key player. Nannochloropsis oceanica is particularly noteworthy for its capability to produce substantial amounts of protein, the vital omega-3 fatty acid EPA, and vitamin K2. But what are the optimal conditions for maximizing production? A study conducted by the DTU National Food Institute reveals that temperature and light are crucial for enhancing the yield of various nutrients.
“A lot of the current research has been concentrating on how Nannochloropsis oceanica grows and generates biomass, along with its fatty acid production. At the DTU National Food Institute, we’ve explored these aspects, but we’ve also compared them with the concurrent production of proteins and vitamin K2,” explains PhD student Emil Gundersen, who carried out the cultivation experiments in the microalgae lab at DTU.
This research presents a broader perspective by analyzing protein content, fatty acid content, vitamin K content, and the growth of the microalgae all at once. This understanding allows for the optimization of the cultivation process to achieve the most nutrient-rich biomass possible.
“Our findings indicate that higher temperatures and increased light intensity promote rapid growth and greater protein production in Nannochloropsis oceanica. However, lowering the temperature enhances the levels of omega-3 and vitamin K2,” adds Emil Gundersen.
Two-Phase Cultivation
Drawing from the research, scientists recommend adopting a two-phase cultivation approach for Nannochloropsis oceanica.
“The study indicates that to yield the best results, the microalgae should first be cultivated at high temperatures and under strong light for optimal growth and protein production. Following this phase, conditions can be modified by reducing the temperature to enable the microalgae to concentrate on producing omega-3 and vitamin K2,” says Emil Gundersen.
The study’s results are derived from the cultivation of modest amounts of microalgae in the lab, yet the researchers anticipate that these trends will be applicable on a larger scale as well.
“Temperature control is a well-understood principle in the fermentation industry, which makes us confident that implementing a two-phase temperature-based approach will be feasible in the future commercial production of microalgae,” states Emil Gundersen.
The Value of Algal Vitamin Production
Vitamin K2 is usually sourced from animal-based foods like meat and dairy, making it more challenging to obtain for those opting for a largely plant-based diet.
“It’s fascinating that microalgae could provide a vegan source of vitamins like K2, which we typically get from animal products,” Emil Gundersen says.
The next phase of research will focus on enhancing the bioavailability of proteins, omega-3 fatty acids, and vitamins present in the microalga. This step is essential because their thick cell walls pose a challenge for human digestion.
Why Grow Microalgae?
Microalgae are organisms that thrive using light and CO2, similar to plants. They can be cultivated in photobioreactors, which consist of systems of plexiglass tubes that provide the necessary light and air for growth.
In comparison to Denmark’s well-established bacterial fermentation industry, the microalgae sector remains relatively small. This is predominantly due to the high-tech indoor systems required for cultivation in Denmark’s climate. In contrast, Southern Europe benefits from a warmer climate that allows for outdoor tank cultivation, which reduces material and energy costs.
Despite this, microalgae are still appealing in cooler climates because of their exceptional nutritional profile, containing essential amino acids, unsaturated long-chain fatty acids, a variety of vitamins, and minerals. Additionally, they can be cultivated on land unsuitable for traditional agriculture and primarily powered by renewable energy sources.
“As microalgae utilize light and CO2, they reduce the need for organic carbon inputs like sugar that are typically necessary in traditional fermentation methods. Furthermore, they require some inorganic nutrients, which can potentially be supplemented through wastewater recycling from other industries,” concludes Emil Gundersen.
