Temperature Effects on Algae Growth, Pigments, and Antioxidants

Greg Howard
26th February, 2025

Temperature Effects on Algae Growth, Pigments, and Antioxidants

Increasing cultivation temperature elevates the concentration of oxidative stress markers malondialdehyde (a) and hydrogen peroxide (b) in Spirulina spp., which demonstrates that temperatures above the 20°C optimum induce cellular stress and inhibit growth.

Image adapted from: Rehman et al. / CC BY (Source)

Key Findings

  • Researchers in Ethiopia discovered that Spirulina grows best at 20°C, with its growth and essential pigments decreasing at higher temperatures
  • When temperatures rise, harmful molecules increase in Spirulina, but the algae respond by producing more protective antioxidants
  • Maintaining optimal temperatures can enhance Spirulina’s nutritional value and resilience, ensuring better quality and yield
Reactive oxygen species (ROS) are molecules that form naturally in living organisms during normal metabolic processes. However, environmental stresses such as high temperatures can increase ROS levels, which can damage cells and impair the growth of organisms. Understanding how different organisms manage ROS is crucial for enhancing their resilience and productivity. A recent study conducted by researchers at the Ethiopian Institute of Agricultural Research[1] explored how varying temperatures affect the growth, pigment production, oxidative stress markers, and antioxidant profiles of Spirulina species, a type of cyanobacteria widely used as a dietary supplement due to its high nutritional value. The study found that Spirulina grows best at 20°C, with growth rates declining at higher temperatures. Pigment levels, including chlorophyll a, chlorophyll b, and carotenoids, also decreased when temperatures exceeded 20°C. These pigments are essential for photosynthesis, the process by which Spirulina converts light energy into chemical energy. The reduction in pigment content at higher temperatures suggests that excessive heat can hinder Spirulina’s ability to perform photosynthesis efficiently, thereby limiting its growth. In addition to growth and pigment production, the researchers examined markers of oxidative stress, specifically malondialdehyde (MDA) and hydrogen peroxide (H2O2). These oxidants increased as the temperature rose, indicating higher levels of oxidative stress in Spirulina cells exposed to heat. To combat this stress, Spirulina produced more antioxidants, including superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX). Antioxidants are molecules that help neutralize ROS, protecting cells from damage. Interestingly, the optimal concentrations of these antioxidants varied with temperature. The highest levels of SOD and POD were observed at 30°C, while CAT and APX peaked at 20°C. This variation suggests that Spirulina adjusts its antioxidant defense mechanisms in response to temperature changes, optimizing protection against oxidative stress under different conditions. Previous research has shown that plants and algae have complex systems to manage ROS and maintain cellular health. For instance, earlier studies demonstrated that enzymes like superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase play crucial roles in reducing ROS levels and preventing oxidative damage in plants under stress[2]. Another study highlighted the importance of antioxidants such as lutein and β-carotene in inactivating ROS, which can damage DNA and contribute to diseases like atherogenesis and carcinogenesis[3]. The findings from the Ethiopian Institute of Agricultural Research build on this knowledge by showing how Spirulina modulates its antioxidant enzymes in response to temperature-induced oxidative stress. To conduct the study, the researchers cultured Spirulina spp. at different temperatures and measured various parameters related to growth, pigment content, oxidative stress markers, and antioxidant enzyme activities. They used spectrophotometric methods to quantify enzyme activities, a technique that allows precise measurement of these biochemical processes. By analyzing the data, the researchers were able to determine the optimal temperature for Spirulina growth and understand how temperature fluctuations impact its biochemical pathways. The implications of this study are significant for both the cultivation of Spirulina and its use as a dietary supplement. In regions where temperatures can vary widely, maintaining optimal growth conditions at around 20°C could maximize biomass production and pigment content, enhancing Spirulina’s nutritional value. Additionally, understanding the antioxidant responses of Spirulina to heat stress can inform strategies to boost its resilience, ensuring consistent quality and yield even under challenging environmental conditions. Furthermore, the study’s insights into the antioxidant mechanisms of Spirulina may have broader applications in biotechnology and medicine. By elucidating how Spirulina manages oxidative stress, researchers can explore ways to enhance its antioxidant properties, potentially leading to the development of more effective dietary supplements or therapeutic agents. This aligns with previous research emphasizing the role of antioxidants in protecting against cellular damage and related diseases[2][3]. Overall, the research from the Ethiopian Institute of Agricultural Research provides a comprehensive understanding of how temperature affects Spirulina’s growth and biochemical functions. By integrating findings from earlier studies on oxidative stress and antioxidant responses, the study offers a nuanced view of the complex interactions between environmental factors and cellular health. This knowledge not only advances our understanding of Spirulina biology but also supports the sustainable cultivation and utilization of this valuable microalga in various industries.

NutritionBiochemPlant Science

References

Main Study

1) Growth of Spirulina spp. at different temperatures and their impact on pigment production, oxidants and antioxidants profile

Published 24th February, 2025

https://doi.org/10.1371/journal.pone.0313350

Related Studies

2) Spectrophotometric assays for antioxidant enzymes in plants.

https://doi.org/10.1007/978-1-60761-702-0_16

3) Effects of temperature and pH on growth and antioxidant content of the microalga Scenedesmus obliquus.

https://doi.org/10.1002/btpr.649


Related Articles

An unhandled error has occurred. Reload 🗙