Polycyclic aromatic hydrocarbons(PAHs)are a class of persistent pollutants with adverse biological effects and pose a serious threat to ecological environments and human health.The previously isolated phenanthrene‐de...Polycyclic aromatic hydrocarbons(PAHs)are a class of persistent pollutants with adverse biological effects and pose a serious threat to ecological environments and human health.The previously isolated phenanthrene‐degrading bacterial consortium(PDMC)consists of the genera Sphingobium and Pseudomonas and can degrade a wide range of PAHs.To identify the degradation mechanism of PAHs in the consortium PDMC,metagenomic binning was conducted and a Sphingomonadales assembly genome with 100%completeness was obtained.Additionally,Sphingobium sp.SHPJ‐2,an efficient degrader of PAHs,was successfully isolated from the consortium PDMC.Strain SHPJ‐2 has powerful degrading abilities and various degradation pathways of high‐molecular‐weight PAHs,including fluoranthene,pyrene,benzo[a]anthracene,and chrysene.Two ring‐hydroxylating dioxygenases,five cytochrome P450s,and a pair of electron transfer chains associated with PAH degradation in strain SHPJ‐2,which share 83.0%–99.0%similarity with their corresponding homologous proteins,were identified by a combination of Sphingomonadales assembly genome annotation,reverse‐transcription quantitative polymerase chain reaction and heterologous expression.Furthermore,when coexpressed in Escherichia coli BL21(DE3)with the appropriate electron transfer chain,PhnA1B1 could effectively degrade chrysene and benzo[a]anthracene,while PhnA2B2 degrade fluoranthene.Altogether,these results provide a comprehensive assessment of strain SHPJ‐2 and contribute to a better understanding of the molecular mechanism responsible for the PAH degradation.展开更多
As one of the most widely distributed bacterial predators in the soil, the role of bacterivorous nematodes on the enhanced bioremediation of polycyclic aromatic hydrocarbon-contaminated soils is crucial, but remains t...As one of the most widely distributed bacterial predators in the soil, the role of bacterivorous nematodes on the enhanced bioremediation of polycyclic aromatic hydrocarbon-contaminated soils is crucial, but remains to be investigated.A microcosm-level study was conducted to examine the effects of bacterial-feeding nematode grazing and tea saponin(TS) addition on bioremediation of a pyrene-contaminated soil enhanced by the polycyclic aromatic hydrocarbon(PAH)-degrading bacterial strain Sphingobium sp.PHE9.After 180 d of incubation, the highest pyrene dissipation(71.3%) was achieved through a combination of Sphingobium sp.PHE9 inoculation with nematode and TS addition.Meanwhile, high counts of culturable PAH-degrading bacteria, soil enzyme activity, and biodiversity indices were observed under the combined treatment, implying that the microbiological function of the contaminated soil was significantly restored.Additionally, the results of Tenax~ extraction with the first-order three-compartment model indicated that rate-limiting factors varied among treatments.The lack of degrading microorganisms was the main rate-limiting factor for the treatments involving TS/nematode addition, and inadequate bioaccessible pyrene was the vital rate-limiting factor in the treatments involving Sphingobium sp.PHE9 inoculation.The proposed combined clean-up strategy proved to be a promising bioremediation technology for aged pyrene-contaminated soils.展开更多
基金This study was supported by grants from the National Key R&D Program of China(2021YFA0909500)Shanghai Excellent Academic Leaders Program(20XD1421900)+1 种基金grants from the National Natural Science Foundation of China(32100075 and 32030004)“Shuguang Program”(17SG09)supported by the Shanghai Education Development Foundation and the Shanghai Municipal Education Commission.
文摘Polycyclic aromatic hydrocarbons(PAHs)are a class of persistent pollutants with adverse biological effects and pose a serious threat to ecological environments and human health.The previously isolated phenanthrene‐degrading bacterial consortium(PDMC)consists of the genera Sphingobium and Pseudomonas and can degrade a wide range of PAHs.To identify the degradation mechanism of PAHs in the consortium PDMC,metagenomic binning was conducted and a Sphingomonadales assembly genome with 100%completeness was obtained.Additionally,Sphingobium sp.SHPJ‐2,an efficient degrader of PAHs,was successfully isolated from the consortium PDMC.Strain SHPJ‐2 has powerful degrading abilities and various degradation pathways of high‐molecular‐weight PAHs,including fluoranthene,pyrene,benzo[a]anthracene,and chrysene.Two ring‐hydroxylating dioxygenases,five cytochrome P450s,and a pair of electron transfer chains associated with PAH degradation in strain SHPJ‐2,which share 83.0%–99.0%similarity with their corresponding homologous proteins,were identified by a combination of Sphingomonadales assembly genome annotation,reverse‐transcription quantitative polymerase chain reaction and heterologous expression.Furthermore,when coexpressed in Escherichia coli BL21(DE3)with the appropriate electron transfer chain,PhnA1B1 could effectively degrade chrysene and benzo[a]anthracene,while PhnA2B2 degrade fluoranthene.Altogether,these results provide a comprehensive assessment of strain SHPJ‐2 and contribute to a better understanding of the molecular mechanism responsible for the PAH degradation.
基金financially supported by the National Natural Science Foundation of China(Nos.41371263 and 41771350)the Fundamental Research Funds for the Central Universities of China(Nos.KYTZ201404 and Y0201700160)+3 种基金the Agricultural Science and Technology Innovation Fund of Jiangsu Province,China(No.CX(17)3047)the Agro-scientific Research in the Public Interest of China(No.201503121)the Environmental Protection Research Project in Jiangsu Province,China(No.2017005)the National Key Research and Development Program of China(Nos.2016YFD0200106 and 2016YFD0300908)
文摘As one of the most widely distributed bacterial predators in the soil, the role of bacterivorous nematodes on the enhanced bioremediation of polycyclic aromatic hydrocarbon-contaminated soils is crucial, but remains to be investigated.A microcosm-level study was conducted to examine the effects of bacterial-feeding nematode grazing and tea saponin(TS) addition on bioremediation of a pyrene-contaminated soil enhanced by the polycyclic aromatic hydrocarbon(PAH)-degrading bacterial strain Sphingobium sp.PHE9.After 180 d of incubation, the highest pyrene dissipation(71.3%) was achieved through a combination of Sphingobium sp.PHE9 inoculation with nematode and TS addition.Meanwhile, high counts of culturable PAH-degrading bacteria, soil enzyme activity, and biodiversity indices were observed under the combined treatment, implying that the microbiological function of the contaminated soil was significantly restored.Additionally, the results of Tenax~ extraction with the first-order three-compartment model indicated that rate-limiting factors varied among treatments.The lack of degrading microorganisms was the main rate-limiting factor for the treatments involving TS/nematode addition, and inadequate bioaccessible pyrene was the vital rate-limiting factor in the treatments involving Sphingobium sp.PHE9 inoculation.The proposed combined clean-up strategy proved to be a promising bioremediation technology for aged pyrene-contaminated soils.
