一株PET降解菌株的筛选鉴定及降解特性

Screening,Identification and Degradation Characteristics of a PET Degrading Strain

本研究进行了聚对苯二甲酸乙二醇酯(polyethyleneterephthalate,PET)降解菌株的分离、筛选和鉴定,以及降解机制的探究。用“分级筛选”策略,先利用塑料类似物对苯二酸二甲酯(diethyl terephthalate,DET)进行富集培养,在以PET颗粒为唯一营养源的无机盐固体培养基上进行涂布,从垃圾填埋场PET塑料样品中筛选获得具有降解PET颗粒能力的菌株JWG-G2。通过菌株形态观察、生理生化特性及16S rRNA序列分析,鉴定该菌株属于微杆菌属(Microbacterium sp.)。菌株JWG-G2在pH 7.0、30℃时生长状态最佳。经菌株JWG-G2处理后,PET颗粒表面酯键特征官能团明显减少;PET颗粒失重率达到1%。菌株JWG-G2能够显著降解PET中间体对苯二酸单羟乙酯钠盐(monohydroxyethyl terephthalate,MHET)和对苯二甲酸双羟乙酯(bishydroxyethyl terephthalate,BHET)多聚体,其降解率分别为4.5%和11.2%。菌株JWG-G2具有较好的PET颗粒及其中间体降解作用,为降解机制的深入研究提供一定理论基础。

The aim was to obtain polyethylene terephthalate(PET)degradation strains,and elaborate its degradation mechanism.Based on"classification screening"strategy,enrichment cultivation was carried out by using plastic analogue dimethyl terephthalate(DET),and then spreading onto separation plates of inorganic salt solid medium that PET particles as the sole nutrient source.Strain JWG-G2 was obtained from PET plastic samples in landfill,which has the ability to degrade PET particles.The strain was identified as Microbacterium sp.by morphological observation,physiological,biochemical characteristics and 16S rRNA sequence analysis.Optimal growth conditions of strain JWG-G2 were pH 7.0 and 30℃.The ester groups on the surface of PET particles were significantly reduced under treatment with strain JWG-G2,and its weight loss rate reached 1%.The strain JWG-G2 was able to degrade the PET intermediate monohydroxyethyl terephthalate(MHET)and bishydroxyethyl terephthalate(BHET)polymers,and the degradation rate was 4.5%and 11.2%.The strain JWG-G2 has good degradation effect on PET particles and its intermediates.It can provide a theoretical basis for the studies of degradation mechanism.