混合菌群YC-BJ1对有机磷阻燃剂的降解及16S rRNA基因多样性分析

Characterization and 16S rRNA gene-based metagenomic analysis of the organophosphorous flame retardants degrading consortium YC-BJ1

摘要:

作为阻燃剂，有机磷酸酯广泛应用于工业制品和人类生活用品中，是一种全球性的环境污染物，因其具有特殊的理化性质，自然条件下很难水解。因此，对有机磷酸酯的微生物降解成了当下的研究热点。通过持续逐级富集，从北京某垃圾处理厂渗透液中富集到一个混合菌群 (编号为YC-BJ1)，并在降解特性、底物谱以及物种组成多样性3个方面对其进行定性鉴定。该菌群能够高效降解磷酸三苯酯 (Triphenyl phosphate, TPhP) 和磷酸三甲苯酯 (Tricresyl phosphate, TCrP)，培养4 d能够实现对100 mg/L TPhP和TCrP的基本降解，降解率分别为99.8%和91.9%。降解特性研究发现，该混合菌群具有出色的环境适应能力，能够在较宽的环境条件下 (温度15–40 ℃, pH 5.0–12.0, 0%–4%盐) 保持对TPhP的降解能力。底物谱分析发现，混合菌群YC-BJ1能够降解部分含氯有机磷阻燃剂，培养4 d，对磷酸三 (1,3-二氯异丙基) 酯 (Tris(1,3-dichloroisopropyl) phosphate, TDCPP) 和磷酸三 (2-氯乙基) 酯 (Tris(2-chloroethyl) phosphate, TCEP) 的降解率分别为16.5%和22.0%。16S rRNA基因物种多样性分析发现，混合菌群YC-BJ1中物种丰度最高的3个菌属分别是生丝微菌属Hyphomicrobium (38.80%)、金黄杆菌属Chryseobacterium (17.57%) 和鞘氨醇盒菌属Sphingopyxis (17.46%)。与目前已报道的有机磷阻燃剂降解菌和菌群相比，混合菌群在降解效率和环境适应能力方面都具有极大的优势，有较广泛的应用空间。高效降解菌群的富集能够为有机磷阻燃剂的降解及其环境污染生物修复提供微生物资源，并为其降解机理的探索提供支持。

Abstract:

As flame retardants, organophosphate is recognized as a global environmental contaminant because of its wide application. This contaminant is hardly degradable by hydrolysis in the environment due to its special physicochemical properties. Therefore, it is of urgent needs to study the microbial degradation of organophosphate. Through continuous enrichment, we isolated one bacterial consortium, named YC-BJ1, from leachate of waste treatment plant in Beijing. The bacterial consortium YC-BJ1 could efficiently degrade 99.8% of triphenyl phosphate (TPhP) and 91.9% of tricresyl phosphate (TCrP) with the concentration of 100 mg/L within 4 days. Besides aryl phosphates, it could degrade chloro-phosphates, tris(1,3-dichloroisopropyl) phosphate (TDCPP) and tris(2-chloroethyl) phosphate (TCEP) by 16.5% and 22.0% respectively. The degradation of the consortium on TPhP was optimized through a broad range of temperature (15–40 ℃), pH (5.0–12.0) and salinity (0%–4%). 16S rRNA gene-based metagenomic analysis revealed that Hyphomicrobium (38.80%), Chryseobacterium (17.57%) and Sphingopyxis (17.46%) were the dominant genera of the consortium YC-BJ1. Compared with the reported organophosphorus flame retardants (OPFRs) degrading bacteria and microflora, the mixed microflora YC-BJ1 exhibited great advantages in degradation efficiency and environmental adaptability, demonstrating its wide application potential. The enrichment and isolation of highly efficient degrading flora can provide abundant microbial resources for the degradation of OPFRs and the bioremediation towards OPFRs-contaminated environments, and also lay a solid foundation for the exploration of its degradation mechanism.