Comparing Oil Production in Different Types of Microalgae

Greg Howard
31st July, 2024

Comparing Oil Production in Different Types of Microalgae

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Wageningen University studied eight microalgal strains to optimize lipid production under different light, temperature, and nitrogen conditions
  • Nitrogen starvation and high light intensity significantly increased lipid content, with Nannochloropsis sp. achieving the highest lipid productivity
  • Microchloropsis gaditana CCFM01 had the highest EPA content under low light and nitrogen-replete conditions, while N. oceanica IMET1 had the lowest
Microalgae are increasingly recognized as a sustainable source of high-value products, particularly for their lipid accumulation capabilities. Lipids, including omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs) like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have significant health benefits, such as enhancing mental health, cognition, and cardiovascular protection[2]. However, large-scale production remains a challenge due to the need for optimal growth conditions and cost-effective processes. A recent study conducted by researchers at Wageningen University[1] focused on the lipid accumulation potential of eight microalgal strains from the genera Nannochloropsis and Microchloropsis. These genera are well-known for their ability to accumulate lipids, which can be used in biofuels and other applications. The study aimed to understand how different light intensities, temperatures, and nitrogen availability affect lipid content and productivity in these strains. The researchers cultivated the microalgae under varying conditions: low light (150 μmol photons m−2 s−1, LL) and high light (600 μmol photons m−2 s−1, HL), temperatures of 15, 25, and 30°C, and both nitrogen-starved (N-) and nitrogen-replete conditions. They monitored biomass, lipid content, and productivity to identify the optimal conditions for lipid accumulation. Under nitrogen starvation and high light conditions, Nannochloropsis sp. exhibited the highest lipid content (59%) and productivity (0.069 g L-1 day-1), while N. oculata had the lowest lipid content (37.5%) and productivity (0.037 g L-1 day-1). This indicates that nitrogen starvation, while detrimental to photosynthesis and growth, can significantly boost lipid accumulation. Similarly, earlier studies have shown that nitrogen starvation triggers lipid accumulation in microalgae, but also negatively impacts growth[3][4]. The study also found that Microchloropsis gaditana CCFM01 achieved the highest EPA content (4.7%) under low light and nitrogen-replete conditions, whereas N. oceanica IMET1 had the lowest EPA content (2.9%) under the same conditions. This suggests that light intensity and nitrogen availability can influence the quality of lipids produced, which is crucial for applications requiring specific fatty acid profiles. Temperature fluctuations also played a significant role in lipid productivity. For instance, under low light and nitrogen-starved conditions at 15°C, Microchloropsis salina demonstrated the highest lipid productivity (0.069 g L-1 day-1), while M. gaditana CCFM01 had the lowest (0.022 g L-1 day-1). This variability underscores the importance of selecting the right strain for specific environmental conditions to maximize lipid yields. The findings align with previous research indicating that light intensity and temperature are critical factors in lipid accumulation. For example, Scenedesmus obliquus showed varying TAG content under different pH and temperature combinations, with the highest fatty acid yield achieved at lower light intensities[4]. Additionally, Chlorella sp. and Monoraphidium sp. demonstrated increased lipid productivity under high light conditions, with significant carbon allocation into lipids[5]. Overall, the study by Wageningen University highlights the importance of optimizing cultivation conditions for different microalgal strains to enhance lipid production. By understanding the physiological responses to light, temperature, and nitrogen availability, researchers can select suitable strains for efficient lipid production. This knowledge is crucial for advancing the microalgal lipid production industry, making it more sustainable and economically viable.

EnvironmentBiotechMarine Biology

References

Main Study

1) Microalgal lipid production: A comparative analysis of Nannochloropsis and Microchloropsis strains

Published 30th July, 2024

https://doi.org/10.1007/s10811-024-03318-7

Related Studies

2) Impact of temperature on fatty acid composition and nutritional value in eight species of microalgae.

https://doi.org/10.1007/s00253-018-9001-x

3) Batch and semi-continuous microalgal TAG production in lab-scale and outdoor photobioreactors.

https://doi.org/10.1007/s10811-016-0897-1

4) Effect of light intensity, pH, and temperature on triacylglycerol (TAG) accumulation induced by nitrogen starvation in Scenedesmus obliquus.

https://doi.org/10.1016/j.biortech.2013.05.105

5) Effect of light intensity on physiological changes, carbon allocation and neutral lipid accumulation in oleaginous microalgae.

https://doi.org/10.1016/j.biortech.2015.05.021


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