聚氨酯塑料降解菌G-11的筛选鉴定及其塑料降解特性

Screening and identification of a polyurethane-degrading bacterium G-11 and its plastic degradation characteristics

摘要:

聚氨酯(polyurethane, PUR)塑料因其特殊的理化性质而被广泛应用。然而，大量废弃PUR塑料的不合理处置造成了严重的资源浪费和环境污染。利用微生物的手段实现废弃PUR塑料的高效降解和循环利用成为目前的研究热点之一，而高效降解菌是PUR塑料生物法处理的关键。本研究以垃圾填埋场PUR类废塑料样品为来源，分离到一株能够降解PUR类似物Impranil DLN的微生物，并对其PUR降解特性开展了研究。通过16S rRNA基因序列比对将该菌初步鉴定为拟无枝杆菌属(Amycolatopsis sp.)，命名为G-11。PUR塑料降解实验结果表明，菌株G-11对商业化PUR塑料的减重率达到4.67%，扫描电镜(scanning electron microscope, SEM)发现塑料结构被破坏，表面出现侵蚀。接触角分析和热重分析(thermogravimetric analysis, TGA)结果发现，菌株G-11处理后的PUR塑料的亲水性增强，热稳定性下降，该结果与减重和扫描电镜结果相一致。结果表明，分离自垃圾填埋场的菌株G-11在废弃PUR类塑料生物降解方面具有一定的应用潜力。

Abstract:

Polyurethane (PUR) plastics is widely used because of its unique physical and chemical properties. However, unreasonable disposal of the vast amount of used PUR plastics has caused serious environmental pollution. The efficient degradation and utilization of used PUR plastics by means of microorganisms has become one of the current research hotspots, and efficient PUR degrading microbes are the key to the biological treatment of PUR plastics. In this study, an Impranil DLN-degrading bacteria G-11 was isolated from used PUR plastic samples collected from landfill, and its PUR-degrading characteristics were studied. Strain G-11 was identified as Amycolatopsis sp. through 16S rRNA gene sequence alignment. PUR degradation experiment showed that the weight loss rate of the commercial PUR plastics upon treatment of strain G-11 was 4.67%. Scanning electron microscope (SEM) showed that the surface structure of G-11-treated PUR plastics was destroyed with an eroded morphology. Contact angle and thermogravimetry analysis (TGA) showed that the hydrophilicity of PUR plastics increased along with decreased thermal stability upon treatment by strain G-11, which were consistent with the weight loss and morphological observation. These results indicated that strain G-11 isolated from landfill has potential application in biodegradation of waste PUR plastics.