一株聚酯型聚氨酯降解菌高地芽孢杆菌YX8-1的分离及鉴定

Isolation and identification of a polyester-polyurethane degrading bacterium Bacillus altitudinis YX8-1

摘要:

聚氨酯(polyurethane, PUR)塑料在日常生活中发挥着重要作用，但同时PUR废弃物也带来严重的环境污染问题。生物(酶)降解是一种环境友好、成本低廉的PUR废弃物回收方法，其关键在于获得高效的降解菌株或酶。本研究从垃圾填埋场的聚氨酯废弃物表面分离出了一株聚酯型PUR降解菌株YX8-1。基于菌落和显微形态观察、16S rDNA和DNA旋转酶(DNA gyrase)基因gyrA系统发育分析及基因组序列比对，将该菌鉴定为高地芽孢杆菌(Bacillus altitudinis)。高效液相色谱(high performance liquid chromatography, HPLC)及液相色谱-质谱联用(liquid chromatography-tandem mass spectrometry, LC-MS/MS)结果显示菌株YX8-1能降解自行合成的聚酯型PUR寡聚物(PBA-PU)，并产生单体化合物4,4′-亚甲基二苯胺。此外，菌株YX8-1能在30 d内使商品化的聚酯型PUR海绵失重32%。本研究为PUR废弃物的生物降解提供了菌株资源，也为挖掘相关降解酶打下了基础。

Abstract:

Although polyurethane (PUR) plastics play important roles in daily life, its wastes bring serious environmental pollutions. Biological (enzymatic) degradation is considered as an environmentally friendly and low-cost method for PUR waste recycling, in which the efficient PUR-degrading strains or enzymes are crucial. In this work, a polyester PUR-degrading strain YX8-1 was isolated from the surface of PUR waste collected from a landfill. Based on colony morphology and micromorphology observation, phylogenetic analysis of 16S rDNA and gyrA gene, as well as genome sequence comparison, strain YX8-1 was identified as Bacillus altitudinis. The results of high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed that strain YX8-1 was able to depolymerize self-synthesized polyester PUR oligomer (PBA-PU) to produce a monomeric compound 4,4′-methylene diphenylamine. Furthermore, strain YX8-1 was able to degrade 32% of the commercialized polyester PUR sponges within 30 days. This study thus provides a strain capable of biodegradation of PUR waste, which may facilitate the mining of related degrading enzymes.