含有苯环结构的PBAT微塑料生物降解对土壤微生物群落结构的影响

Effects of biodegradation of PBAT microplastics with benzene ring structure on soil microbial community structure

为进一步探明以对苯二甲酸(PTA)作为合成单体的聚对苯二甲酸-己二酸丁二醇酯(PBAT)在生物降解过程中,是否会产生类似于其它芳香类有机污染物的毒性效应,本研究以PBAT微塑料为研究对象,同时以PTA为参照,通过高通量测序考察不同粒径、不同添加量的PBAT微塑料的生物降解对土壤微生物群落结构的影响,分析评价PBAT微塑料的毒性-剂量效应.结果表明,PBAT微塑料的降解率与其添加量、粒径大小及填埋时间有关;PBAT微塑料的粒径、添加量以及填埋时间的不同会导致土壤样本中细菌群落相对丰度的动态变化,进而影响微生物群落结构,且与PTA存在差异,可能与其苯环结构有关.PBAT微塑料的添加降低了土壤中变形菌门和放线菌门丰度,但提高了酸杆菌门丰度.本研究结果对评价土壤中PBAT微塑料的生态风险、开发可有效降解微塑料的微生物资源具有重要意义.

In order to further investigate whether poly(butylene terephthalate adipate)(PBAT)with terephthalic acid(PTA)as the synthetic monomer will produce toxic effects similar to other aromatic organic pollutants in the process of biodegradation,PBAT micro plastics were used as the research object and PTA as the reference.The effects of biodegradation of PBAT micro plastics with different particle sizes and different amounts on soil microbial community structure were investigated by high-throughput sequencing,and the toxicity-dose effect of PBAT micro plastics was analyzed and evaluated.The results showed that the degradation rate of PTA micro plastics was related to its addition amount,particle size and landfill time,and the difference of PBAT micro plastics particle size,particle size and landfill time would lead to the dynamic change of the relative abundance of bacterial community in soil samples,and then affect the microbial community structure,which was different from PBAT micro plastics,which may be related to its benzene ring structure.The addition of PBAT micro plastics decreased the abundance of Proteobacterium and Actinomycetes in soil,but increased the abundance of Acidobacteriota.The results of this study are of great significance for evaluating the ecological risk of PBAT micro plastics in soil and developing microbial resources that can effectively degrade micro plastics.