低分子量多环芳烃降解菌的筛选、菌群构建及降解机制  

Screening of low-molecular-weight polycyclic aromatic hydrocarbons degrading strains,construction of bacterial consortium,and degradation mechanism

作　　者：赵博 荆佳维 王婷婷 杨颖 曲媛媛[1] ZHAO Bo;JING Jiawei;WANG Tingting;YANG Ying;QU Yuanyuan(Key Laboratory of Industrial Ecology and Environmental Engineering of Ministry of Education,School of Environment,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学环境学院工业生态与环境工程教育部重点实验室,辽宁116024

出　　处：《应用与环境生物学报》2024年第2期317-323,共7页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(31970107);哈尔滨工业大学城市水资源与水环境国家重点实验室开放课题(QAK201943);国家重点研发计划项目(2018YFC1602306)资助。

摘　　要：菲和芘作为低分子量多环芳烃代表物质,具有溶解度低、难降解和毒性高等特点.多环芳烃污染场地中通常有多种污染物共存,且单一菌株降解能力有限,因此研究复合菌群降解混合底物对处理多环芳烃污染具有实际意义.从石油污染土壤中筛选出两株低分子量多环芳烃降解菌,经16S rRNA序列比对鉴定为纤维菌属和布鲁氏菌属,分别命名为Cellulosimicrobium sp.RS和Brucella sp.BZ.结果显示,两株细菌均能以菲或芘为唯一碳源生长,菌株RS、BZ在120 h内对100 mg/L菲的降解率分别为44.10%、34.20%,对100 mg/L芘的降解率分别为22.50%、25.30%.利用正交试验确定菌株RS、BZ构建成复合菌群PP-RSBZ的比例,并通过单因素法考察了pH对降解效果的影响.在菌株RS:BZ=3:1(V/V)、pH=7时,复合菌群PP-RSBZ在120 h内对菲和芘混合底物(150 mg/L)的降解率最高,为45.63%,相比单一菌株提高了1.65-1.84倍.通过全基因组测序结果,确定菌株存在的基因,进而推测了菌群对菲和芘的生物降解途径.本研究为低分子量多环芳烃的降解提供了新颖的菌株资源,构建了降解混合底物的复合菌群及适合条件,并推测了降解途径.(图6表3参30)Representative substances of low-molecular-weight polycyclic aromatic hydrocarbons(PAHs),phenanthrene and pyrene,are characterized by low solubility,difficult degradation,and high toxicity.Many types of pollutants coexist in actual PAHs and PAH-contaminated sites.The degradation ability of a single strain is limited;therefore,the degradation of mixed substrates by compound bacteria to treat PAH contamination must be crucially studied.In this study,two strains of low-molecular-weight PAH-degrading bacteria,RS and BZ,were screened from petroleum-contaminated soil and identified by 16S rRNA sequence comparison as Cellulosimicrobium and Brucella respectively.Both strains grew using phenanthrene and pyrene as the sole carbon sources.Within 120 h,strains RS and BZ exhibited 44.10%and 34.20%phenanthrene degradation and 22.50%and 25.30%pyrene degradation,respectively.An orthogonal experiment was used to determine the ratio of strains RS and BZ constructed into the PP-RSBZ complex bacteria.The effects of pH and the concentration of additional high-quality carbon sources on the degradation were investigated using the singlefactor method.The results demonstrated that under the conditions of strain RS:BZ=3:1(V/V),pH=7,the degradation efficiency of PP-RSBZ for phenanthrene and pyrene mixed substrate was 45.63%in 120 h,which was 1.65–1.84 times higher than that of the single strain.The biodegradation pathways of phenanthrene and pyrene were estimated using whole-genome sequencing.This study provides novel strains for degrading lowmolecular-weight PAHs.Complex bacteria were constructed to degrade the mixed substrate,degradation conditions were optimized,and degradation pathways were speculated.

关 键 词：纤维菌属 布鲁氏菌属 低分子量多环芳烃 降解机制 复合菌群 

分 类 号：X70[环境科学与工程—环境工程]