As microplastics accumulate in soils, waters, and even the human body, scientists are racing to understand how these persistent pollutants can be safely removed from the environment. A new review published in New Contaminants highlights a critical but often overlooked factor in this challenge: temperature.
The study examines how high and extreme temperatures influence the ability of microorganisms to degrade microplastics. Drawing on evidence from laboratory studies, natural hot environments, and industrial systems, the authors show that heat can both accelerate and suppress microbial breakdown of plastic particles, depending on conditions and the organisms involved.
Microplastics are plastic fragments smaller than five millimeters that originate from the breakdown of larger plastic items or are manufactured directly for industrial use. Once released, they can persist for decades to centuries, entering food chains and posing risks to ecosystems and human health.
Microbial degradation has emerged as a promising, environmentally friendly approach for addressing microplastic pollution. Certain bacteria, fungi, and algae can attach to plastic surfaces and secrete enzymes that break long polymer chains into smaller molecules, eventually converting them into carbon dioxide, water, and biomass. However, the efficiency of this process depends strongly on temperature.
"Temperature acts like a double edged sword for microbial degradation of microplastics," said corresponding author Lei Tang of Nanjing Agricultural University. "Moderate warming can make plastics easier for microbes to attack, but extreme heat can also damage microbial cells and deactivate key enzymes."
According to the review, elevated temperatures can soften plastics and reduce their crystallinity, increasing the mobility of polymer chains and making them more accessible to microbial enzymes. In some cases, heating plastics to near their glass transition temperature significantly boosts degradation rates.
At the same time, extreme heat can overwhelm many common microorganisms. Enzymes may denature, cell membranes can lose integrity, and entire microbial communities may collapse. As global warming increases the frequency and intensity of heat waves, these opposing effects are becoming increasingly relevant in natural and engineered environments.
The authors point to thermophilic microorganisms, which thrive at high temperatures, as a potential solution. These heat loving microbes are found in hot springs, composting systems, and geothermal soils, and some have already demonstrated the ability to degrade plastics such as polyethylene, polyethylene terephthalate, and polylactic acid at temperatures above 50 degrees Celsius.
"Thermophiles produce enzymes that remain stable and active at temperatures that would disable ordinary microbes," Tang explained. "These organisms represent an underexplored resource for plastic biodegradation under warming conditions."
Beyond natural thermophiles, the review highlights advances in enzyme engineering, genetic modification, and synthetic microbial consortia. By redesigning enzymes or constructing microbial communities with complementary functions, researchers are beginning to build systems that maintain high degradation efficiency even under extreme thermal stress.
However, the authors caution that significant challenges remain. High costs, slow degradation rates, limited effectiveness for certain plastic types, and potential ecological risks associated with releasing engineered microbes all need careful consideration.
"Microbial solutions are not a silver bullet," said Tang. "But by understanding how temperature controls both plastics and microbes, we can design smarter and safer strategies for reducing microplastic pollution."
The review concludes that integrating thermophilic microbes, engineered enzymes, and optimized environmental conditions could play a key role in future microplastic remediation efforts, especially in a warming world.
As climate change reshapes ecosystems worldwide, understanding how heat affects the natural cleanup power of microbes may be essential for managing one of the planet's most persistent pollutants.
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Journal reference: Yuan Z, Lv R, Gudda F, Mosa A, Oleszczuk P, et al. 2025. Impacts of high temperatures on microbial degradation of microplastics and strategies for optimization. New Contaminants 1: e018
https://www.maxapress.com/article/doi/10.48130/newcontam-0025-0019
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About the Journal:
New Contaminants is an open-access journal focusing on research related to emerging pollutants and their remediation.
