Thriving algae in polluted water symbolizes sustainable solutions.

Unlock Algae's Potential: How to Grow Super Algae Even With Pollution

Jordan Keane in Climate & Environment September 2025 • 4 min read.

"Discover how a unique growth method allows algae to thrive, even in polluted conditions, potentially revolutionizing biofuel and sustainable practices."

Microalgae are gaining attention for their potential in biofuels, health products, and even food. However, their growth can be hindered by various environmental factors, especially nitrogen pollution in the form of ammonium.

Ammonium, while a preferred nitrogen source for some algae, becomes toxic at high concentrations. This poses a challenge, especially when considering using wastewater (often rich in ammonium) for algae cultivation. Scientists are exploring innovative ways to overcome this hurdle and unlock the full potential of these tiny powerhouses.

This article dives into research on how a special cultivation method can help microalgae not only tolerate but thrive in the presence of ammonium, paving the way for sustainable biofuel production and effective wastewater treatment.

Mixotrophic Cultivation: The Key to Ammonium Tolerance

Thriving algae in polluted water symbolizes sustainable solutions.

The study focuses on a specific microalga, Spirulina platensis, and its ability to grow in a mixotrophic environment. Mixotrophic cultivation involves providing algae with both light and organic carbon sources (like glucose), allowing them to utilize different energy pathways. Researchers compared this method to autotrophic cultivation (relying solely on light) to see how it affected ammonium tolerance.

The results revealed that mixotrophic cultivation significantly improved Spirulina platensis's ability to withstand ammonium toxicity. Here's a breakdown:

Enhanced Growth: Algae grown mixotrophically showed better growth and a stronger tolerance to high ammonium levels compared to those grown autotrophically.
Protein Boost: The protein content in the algae increased with higher nitrogen concentrations, showcasing the algae's ability to utilize ammonium effectively.
Lipid Production: While ammonium decreased lipids in autotrophic cultivation, it surprisingly increased lipid production in the mixotrophic setup. Lipids are crucial for biofuel production.
Photosynthesis Protection: Mixotrophic cultivation induced a stronger photosystem protection mechanism, allowing the algae to maintain photosynthetic activity even under ammonium stress.

The researchers found that adding organic carbon allows algae to better assimilate ammonium, reducing its toxic effects. The algae's photosynthetic machinery was less inhibited, leading to more robust growth and productivity.

The Future of Algae: Cleaning Water and Fueling the World

This research highlights the potential of mixotrophic cultivation to unlock the full potential of microalgae, even in challenging environments. By understanding how algae respond to ammonium under different conditions, scientists can optimize growth strategies for various applications.

The implications are far-reaching. Imagine using algae to treat wastewater, simultaneously removing pollutants and producing valuable biofuels. This approach offers a sustainable solution to two pressing global challenges: pollution and energy security.

Further research is needed to refine mixotrophic cultivation techniques and explore the use of different organic carbon sources. However, this study provides a promising step towards a future where algae play a central role in a cleaner, more sustainable world.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.biortech.2018.11.042, Alternate LINK

Title: Effect Of Ammonium Nitrogen On Microalgal Growth, Biochemical Composition And Photosynthetic Performance In Mixotrophic Cultivation

Subject: Waste Management and Disposal

Journal: Bioresource Technology

Publisher: Elsevier BV

Authors: Xiaoting Li, Wei Li, Jun Zhai, Haoxuan Wei, Quanfeng Wang

Published: 2019-02-01

Everything You Need To Know

What are microalgae, and why are they important?

Microalgae, especially Spirulina platensis, are cultivated for biofuels, health products, and food. Their significance lies in their potential to address environmental and energy challenges. The implications of this cultivation are widespread. Their use in biofuels offers a sustainable alternative to fossil fuels. In wastewater treatment, microalgae can remove pollutants. In the health industry, they can provide nutritional supplements.

Why is ammonium a problem for growing microalgae?

Ammonium is a form of nitrogen pollution that can be toxic to microalgae at high concentrations. This toxicity hinders algae growth, especially when using wastewater (often rich in ammonium) for cultivation. The implications of this toxicity are that it limits the potential of microalgae for biofuel production and wastewater treatment. Understanding how to mitigate ammonium toxicity is essential for harnessing algae's full potential.

What is mixotrophic cultivation, and why is it significant?

Mixotrophic cultivation is a method of growing microalgae that provides both light and organic carbon sources (like glucose). This approach allows microalgae to use different energy pathways. It's significant because, in the context of this research, it enhances the ability of Spirulina platensis to tolerate ammonium toxicity. The implications are that mixotrophic cultivation opens doors to cultivate microalgae in environments with high ammonium concentrations, such as wastewater, leading to more efficient biofuel production and wastewater treatment.

What role did Spirulina platensis play in the study?

Spirulina platensis, a specific type of microalgae, was used in the research. It was chosen to study the impact of ammonium on algae growth. The implications are that it helped reveal how different cultivation methods, specifically mixotrophic cultivation, can help this specific algae species thrive in conditions with high ammonium levels. The results provide insights that can be applied to other species and improve the efficiency of microalgae cultivation for various applications.

What are the main findings of this research and what are the implications?

The research indicates that mixotrophic cultivation helps Spirulina platensis to better withstand ammonium toxicity. The key findings include enhanced growth, increased protein content, improved lipid production (crucial for biofuel), and protection of the photosynthetic machinery. These results show that by adding organic carbon, algae can assimilate ammonium more effectively. The implications are increased efficiency in biofuel production, effective wastewater treatment, and potentially, applications in other areas where algae cultivation can be used.