微塑料与土壤环境中微生物互作研究进展

作为环境中广泛存在的污染物,微塑料(microplastics)的相关研究备受关注。基于已有研究,本文综合分析了微塑料与土壤微生物(soil microorganisms)的互作关系,微塑料会通过直接或间接的方式影响微生物群落结构与多样性,影响的程度取决于微塑料的类型、剂量和形状。土壤微生物会通过形成表面生物膜和群落选择效应来适应微塑料这一外来物所引起的变化。本文还特别关注了微塑料的生物降解机理,同时探究了影响这一过程的因素,微生物首先会定殖在微塑料表面,分泌多种胞外酶在特定位点发挥作用,将聚合物转化成低聚物或单体,解聚的小分子进入胞内进一步分解代谢,而影响这一降解过程的因素除了分子量、密度、结晶度等微塑料自身理化性质,还包括一些生物因素和非生物因素对相关微生物生长代谢和酶活性的作用。未来研究应注重与实际环境的联系,在深入探究微塑料生物降解研究的同时,开发解决微塑料污染问题的新技术。

Interaction between microplastics and microorganisms in soil environment: a review

As a widespread pollutant in the environment, research on microplastics have attracted much attention. This review systematically analyzed the interaction between microplastics and soil microorganisms based on existing literatures. Microplastics can change the structure and diversity of soil microbial communities directly or indirectly. The magnitude of these effects depends on the type, dose and shape of microplastics. Meanwhile, soil microorganisms can adapt to the changes caused by microplastics through forming surface biofilm and selecting population. This review also summarized the biodegradation mechanism of microplastics, and explored the factors affecting this process. Microorganisms will firstly colonize the surface of microplastics, and then secrete a variety of extracellular enzymes to function at specific sites, converting polymers into lower polymers or monomers. Finally, the depolymerized small molecules enter the cell for further catabolism. The factors affecting this degradation process are not only the physical and chemical properties of the microplastics, such as molecular weight, density and crystallinity, but also some biological and abiotic factors that affect the growth and metabolism of related microorganisms and the enzymatic activities. Future studies should focus on the connection with the actual environment, and develop new technologies of microplastics biodegradation to solve the problem of microplastic pollution.