降解聚乙烯塑料芽孢杆菌LC-2的分离鉴定及降解特性研究

塑料在环境中不断地积累，逐渐破碎成为尺寸小于5 mm的微塑料，对环境和人类健康构成严重威胁。本研究从青岛李村河口采集的塑料薄膜上分离出一株能够降解聚乙烯(PE)的细菌，命名为LC-2，通过分子生物学结合形态学和生理生化特征分析将其鉴定为芽孢杆菌(Bacillus aquimaris)。在以PE为唯一碳源的液体培养基中，接种该细菌培养28 d后，通过扫描电镜、接触角测定、热重分析以及傅里叶变换红外光谱等手段分析表明，PE的失重率在9%左右，表面形貌发生变化，疏水性变小且表面发生氧化，产生?C=O官能团，这些证据足以证明LC-2可以降解PE。

Isolation,identification and polyethylene-degrading characteristics of Bacillus LC-2

Plastics accumulate in the environment and gradually break into microplastics (MPs, size below 5 mm). It poses a serious threat to the environment and human health. In this study, a strain LC-2 capable of degrading polyethylene (PE) was isolated from plastic films collected from the Licun Estuary of Qingdao. It was identified as Bacillus aquimaris by using a combination of molecular biological technique with morphological, physiological and biochemical characteristics. After the strain was isolated, it was cultured in a liquid medium for 28 days with PE as the sole carbon source. The polyethylene was subsequently separated and examined with a scanning electron microscopy, a contact angle test, a thermogravimetric analysis and a Fourier transform infrared spectrum analysis. The results showed that the weight loss of PE was about 9% after the degradation, with apparent morphologic changes on the surface of PE. It was also showed that the hydrophobicity of PE became smaller, with surface oxidation to produce ?C=O functional groups. These evidences are sufficient to prove that the strain LC-2 can degrade PE.