不同石油污染程度土壤细菌群落多样性及优势菌群分析

Bacterial Community Diversity and Dominant Taxa in Soils with Different Petroleum Pollution Levels

    摘要
  • 摘要:
      目的  探究辽河油田不同石油污染程度土壤中理化性质及细菌群落多样性和组成的变化规律，并对石油污染土壤中的石油降解菌进行分离培养和鉴定。
      方法  采集了辽河油田不同石油污染程度土壤，采用高通量测序技术和化学分析法对土壤细菌群落组成和土壤理化性质进行测定，并进一步筛选出石油降解菌株。
      结果  在出油口（A）、距离出油口50 m（B）和距离出油口150 m（C）采集的三个土壤样品，其土壤总石油烃含量分别为2467.44 mg kg−1、884.99 mg kg−1和141.63 mg kg−1，三个土壤样品具有不同的石油污染程度。石油污染显著提高了土壤总有机碳含量，土壤总石油烃含量与总有机碳含量呈现正相关（P < 0.001）。土壤细菌群落多样性和丰富度指数与土壤石油烃的浓度呈显著负相关（P < 0.01）。不同石油污染程度土壤具有不同的细菌群落组成和结构，土壤石油烃含量是影响细菌群落变化的主要因素。出油口石油污染土壤样品（A）中，变形菌门（Proteobacteria）为优势菌门，假单胞菌属（Pseudomonas）、假黄单胞菌属（Pseudoxanthomonas）、博代氏杆菌属（Bordetella）和伯克氏菌属（Burkholderia）为优势菌属。从出油口石油污染土壤（A）中分离出3株石油降解菌株，通过16S rRNA基因测序分别被鉴定为Pseudomonas baetica、黄褐假单胞菌（Pseudomonas fulva）和施氏假单胞菌（Pseudomonas stutzeri），其石油降解率分别为37.2%、46.9%和57.8%。此结果与A样品高通量测序属水平组成分析相吻合，表明石油污染能够选择性富集土壤中具有石油降解能力的假单胞菌属。
      结论  石油污染提高了土壤总有机碳含量，降低了土壤细菌群落多样性，富集了具有烃类降解能力的优势菌属，是造成土壤细菌群落组成和结构改变的主要因素，并筛选出具有潜在开发应用价值的石油降解假单胞菌株。

     

    Abstract:
      Objective  This study was carried out to elucidate the variation of soil physicochemical properties and bacterial community in soils with different petroleum pollution levels in Liaohe oil field.
      Method  The soil bacterial community and soil physiochemical properties were examined by Illumina MiSeq sequencing and chemical analysis. In addition, some efficient oil-degrading strains were isolated.
      Result  The results showed that the total petroleum hydrocarbon (TPH) contents in soils collected from oil outlet (A), 50 m (B) and 150 m (C) away from the oil outlet were 2467.44, 884.99 and 141.63 mg kg−1, respectively. The results of soil physiochemical properties showed that petroleum pollution significantly increased soil total organic carbon (TOC) content. And, positive correlation between the TPH content and the TOC content was observed (P < 0.001). The results of MiSeq sequencing showed that the soil bacterial community diversity and richness index were negatively correlated with the TPH content (P < 0.01). Distinct soil bacterial community composition and structure were observed among soil samples with different levels of petroleum pollution. Correlation analysis showed that soil TPH content was the main factor of community dissimilarity. Moreover, the bacterial community composition analysis demonstrated that Proteobacteria (in phylum level) and Pseudomonas, Pseudoxanthomonas, Bordetella and Burkholderia (in genus level) were selectively enriched in oil outlet soil (A). Further, three oil-degrading strains were isolated from oil outlet soil (A). The isolated strains were identified as Pseudomonas baetica, Pseudomonas fulva, and Pseudomonas stutzeri, with oil degradation rates of 37.2%, 46.9% and 57.8%, respectively. These results were consistent with the results of composition analysis in genus level in oil outlet soil (A), suggesting that petroleum pollution could selectively enrich oil-degrading Pseudomonas strains in soil.
      Conclusion  Petroleum pollution significantly increases soil TOC content, decreases the diversity of soil bacterial community, enriches the hydrocarbon-degrading taxa, and contributes to the soil bacterial community dissimilarity. Moreover, the isolated candidate strains of Pseudomonas can be used for bioremediation of petroleum-contaminated soil.

     

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