ABSTRACT

Bioremediation is among the most basic and reliable way to eliminate pollutants by transforming the toxic petroleum components into less toxic metabolites. In order to compare the change of bacterial community during oil-biodegradation process, two oil-polluted sediments sampled from Tunisia were analyzed using 16S rDNA clone libraries. During the experimental period, measurements of microbial abundance along with qualitative and quantitative analysis of pollutants were carried out. Fingerprinting analysis of natural samples showed the presence of different classes of bacteria with the dominance of Gammaproteobacteria (>60%). The bacterial diversity decreased in enrichment cultures with crude oil with the appearance and predominance of Alcanivorax spp. Our data also showed that several Obligate Marine Hydrocarbonoclastic Bacteria (OMHB: Alcanivorax, Cycloclasticus and Marinobacter) were stimulated by the addition of petroleum. The shift of diversity and the dominance of OMHB were associated with high degradation rate of crude oil (the total degradation of petroleum TERHCs was estimated at 90% and 70% in TST1E and TST2E) and a decrease in sediment toxicity to Corophium orientale. Since several factors can influence the clean-up in-field, the effectiveness of biostimulation treatment and its optimization at lab scale under controlled conditions would facilitate and allow the application in-situ. Moreover, the study of the community diversity allows the detection and the identification of the dominant hydrocarbonoclastic species such as Alcanivorax which it would be beneficial in future experiments to facilitate the selection of the autochthonous strains (adapted to support the contamination) for the reconstruction of efficient consortia useful in the cleanup of hydrocarbon contaminated sites.

摘要

生物修复是通过将有毒的石油成分转化为毒性较小的代谢物来消除污染物的最基本和最可靠的方法之一。为了比较石油生物降解过程中细菌群落的变化，使用 16S rDNA 克隆文库分析了从突尼斯取样的两个石油污染沉积物。在实验期间，进行了微生物丰度的测量以及污染物的定性和定量分析。天然样品的指纹图谱分析显示存在不同种类的细菌，其中以Gammaproteobacteria 为主（>60%）。在以Alcanivorax spp的外观和优势的原油富集培养物中细菌多样性降低. 我们的数据还显示，添加石油刺激了几种专性海洋烃类细菌（OMHB： Alcanivorax、Cycloclasticus 和 Marinobacter） 。多样性的转变和 OMHB 的优势与原油的高降解率（在 TST1E 和 TST2E 中石油 TERHC 的总降解率估计为 90% 和 70%）和沉积物对东方珊瑚的毒性降低有关. 由于有几个因素会影响现场清理，生物刺激处理的有效性及其在受控条件下在实验室规模的优化将促进并允许现场应用。此外，对群落多样性的研究可以检测和识别主要的烃类碎屑物种，如Alcanivorax，这将有助于未来的实验选择本地菌株（适应于支持污染）以重建高效联合体可用于清理碳氢化合物污染场地。