一株聚乙烯塑料降解细菌的分离、鉴定及其降解特性

Isolation, identification, and degradation characterization of a polyethylene plastic-degrading bacterial strain

摘要:

聚乙烯(polyethylene, PE)因其优异的性能被广泛应用。然而，废弃聚乙烯的不合理处置造成严重的环境污染。聚乙烯微生物降解是一种低碳、环保的高效同级回收利用方法，利用微生物降解技术处理聚乙烯废弃物成为当前研究的热点之一。采用富集培养方法从垃圾填埋场废弃塑料中筛选出一株PE降解菌株ETX1, 初步鉴定该菌为赖氨酸杆菌(Lysinibacillus sp.)。菌株ETX1孵育PE粉末20 d后，粉末减重29.41%；傅里叶变换红外光谱(fourier transform infrared spectroscopy, FTIR)显示粉末出现羰基、羟基等特殊吸收峰，证实ETX1具有PE降解效果；通过PE膜片质量损失、FTIR、扫描电镜(scanning electron microscopy, SEM)、接触角(contact angle, CA)表征其降解效果，结果显示ETX1在120 d内能使膜片减重达5.23%，膜片结构遭到破坏，膜表面侵蚀形成孔洞，亲水性增强，并且出现更强的羰基吸收峰。PE降解菌株ETX1的发现，不仅丰富了PE塑料降解菌株资源，也为挖掘高效PE降解元件、获得降解酶，以及解析相关降解途径等奠定了基础。

Abstract:

Polyethylene (PE) is widely used due to its excellent properties. However, the improper disposal of PE waste has led to serious environmental pollution. Microbial degradation of PE is a low-carbon, environmentally friendly, and highly efficient method of homogeneous recycling. The use of microbial degradation technology to treat polyethylene waste has become one of the current research hotspots. As a result, employing microbial degradation technology to address polyethylene waste has become a key focus of current research. A PE-degrading strain ETX1 was screened from waste plastics in a landfill by the enrichment culture method. The strain was identified as Lysinibacillus sp.. After incubating PE powder with the strain for 20 days, a weight loss of 29.41% was observed. Fourier transform infrared spectroscopy (FTIR) showed that special absorption peaks such as carbonyl and hydroxyl groups appeared, proving that ETX1 had the effect of degrading PE. The degradation effect of this strain was characterized by the weight loss of PE film, FTIR, scanning electron microscopy, and contact angle. The results showed that ETX1 reduced the PE film weight by up to 5.23% within 120 days. The film structure was damaged, with holes formed by erosion on the film surface, and the hydrophilicity was enhanced. Additionally, a stronger carbonyl absorption peak appeared. The discovery of the PE-degrading strain ETX1 not only enriches the resources of PE plastic-degrading strains but also lays a foundation for mining efficient PE-degrading elements, obtaining degrading enzymes, and deciphering related degradation pathways.