Impacts of high temperatures on microbial degradation of microplastics and strategies for optimization

The extensive use and improper disposal of plastics have led to severe environmental pollution, with the potential for microplastic accumulation in humans posing significant health risks. Microbial degradation has emerged as a research focus in the control of plastic pollution due to its ecological sustainability and substrate specificity. The efficiency of microbial degradation is temperature-dependent. Moderate increases in temperature can decrease the hardness and crystallinity of microplastics (MPs), thereby facilitating microbial activity and degradation. However, excessively high temperatures may activate microorganisms and denature proteins, resulting in diminished degradation. Against the backdrop of global warming and rising temperatures, studying the impact of extreme heat on microbial degradation of MPs is important. Research has shown that under extremely high temperature conditions, certain naturally occurring thermophilic microorganisms exhibit considerable potential for MP degradation. To enhance the heat resistance of degrading microbial communities and improve microplastic degradation efficiency, this review proposes multiple strategies, including exploring natural thermophilic microbial resources, enhancing the thermal stability and activity of degrading enzymes through enzyme engineering, and constructing heat-resistant engineered strains and synthetic microbial consortia. Simultaneously, limitations of current technologies are summarized, and future directions for improvement are suggested, providing a reference for further research, and offering technical insights into the high-temperature biodegradation of other pollutants.