Water temperature at which anaerobic microbes become active

Anaerobic microbes become active at a wide range of water temperatures, depending on the specific type of microorganism and environmental conditions. However, research and studies indicate that their activity generally begins at temperatures above 15°C, with optimal ranges varying based on whether they are psychrophilic, mesophilic, or thermophilic.

• General Threshold for Activity: Anaerobic activity is notably reduced below 15°C, and biological activity virtually ceases when water temperatures drop below freezing. For anaerobic lagoons, for instance, maintaining temperatures between 25°C and 40°C is ideal for the performance of methanogenic bacteria, which are crucial in anaerobic processes^[1].
• Psychrophilic Range: Some anaerobic microbes can function at lower temperatures, below 20°C, though their activity is slower compared to higher temperature ranges^[2].
• Mesophilic Range: Many anaerobic microbes thrive in moderate temperatures between 20°C and 43°C, with an optimum around 35°C to 37°C. This range is common for processes like anaerobic digestion in wastewater treatment^[2].
• Thermophilic Range: Certain anaerobic microbes are active at higher temperatures, between 50°C and 60°C, with optimal performance often seen in this range for specific industrial applications like anaerobic digestion^[2]. Some thermophilic archaea and bacteria can even function at temperatures exceeding 60°C, up to 110°C in extreme environments like hydrothermal vents^[3][4][5].

Temperature plays a critical role in regulating the metabolic activity and microbial community structure of anaerobic microbes. Below 15°C, their activity significantly declines, while above this threshold, different groups of anaerobic microbes become active depending on their temperature tolerance and optimal growth conditions^[6][7][1].

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• https://www3.epa.gov/npdes/pubs/alagoons.pdf  
• https://www.sciencedirect.com/science/article/abs/pii/S136403212100736X   
• https://www.britannica.com/science/bacteria/Physical-requirements 
• https://www.nature.com/articles/srep17056 
• https://courses.lumenlearning.com/suny-microbiology/chapter/temperature-and-microbial-growth/ 
• https://www.sciencedirect.com/science/article/abs/pii/S0960852416302784 
• https://pmc.ncbi.nlm.nih.gov/articles/PMC11237690/