In this study, derivatives of two common fatty acids in plant root exudates, sodium palmitate and sodium linoleate (sodium aliphatates), were added to an aged Polycyclic aromatic hydrocarbons (PAHs) contaminated soil to estimate their effectiveness in the removal of PAHs. Sodium linoleate was more effective in lowering PAHs and especially high-molecular-weight (4-6 ring) PAHs (HMW-PAHs). Principal coordinates analysis (PCoA) indicates that both amendments led to a shift in the soil bacterial community. Moreover, linear discriminant effect size (LEfSe) analysis demonstrates that the specific PAHs degraders Pseudomonas, Arenimonas, Pseudoxanthomonas and Lysobacter belonging to the γ-proteobacteria and Nocardia and Rhodococcus belonging to the Actinobacteria were the biomarkers of, respectively, sodium linoleate and sodium palmitate amendments. Correlation analysis suggests that four biomarkers in the sodium linoleate amendment treatment from γ-proteobacteria were all highly linearly negatively related to HMW-PAHs residues (p < 0.01) while two biomarkers in the sodium palmitate amendment treatment from Actinobacteria were highly linearly negatively related to LMW-PAHs residues (p < 0.01). Higher removal efficiency of PAHs (especially HMW-PAHs) in the sodium linoleate amendment treatment than in the sodium palmitate amendment treatment might be ascribed to the specific enrichment of microbes from the γ-proteobacteria. The bacterial functional KEGG orthologs (KOs) assigned to PAHs metabolism and functional C23O and C12O genes related to cleavage of the benzene ring were both up-regulated. These results provide new insight into the mechanisms of the two sodium aliphatate amendments in accelerating PAHs biodegradation and have implications for practical application in the remediation of PAHs-contaminated soils.

中文翻译：

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评估脂肪酸衍生物在多环芳烃污染的土壤和微生物群落的修复中的作用以及降解基因的响应。

在这项研究中，将植物根系分泌物中的两种常见脂肪酸的衍生物，棕榈酸钠和亚油酸钠（脂酸钠）添加到老化的多环芳烃（PAHs）污染的土壤中，以评估其去除PAHs的有效性。亚油酸钠在降低多环芳烃尤其是降低高分子量（4-6环）多环芳烃（HMW-PAHs）方面更有效。主坐标分析（PCoA）表明，这两种修正均导致土壤细菌群落的变化。此外，线性判别效应量（LEfSe）分析表明，属于γ-变形杆菌的特定PAHs降解物假单胞菌，槟榔属，假黄单胞菌和溶菌属，属于放线菌的诺卡氏菌和红球菌分别是亚油酸钠和棕榈酸钠的生物标记。相关分析表明，来自γ-变形杆菌的亚油酸钠修饰处理中的四个生物标志物均与HMW-PAHs残留高度线性负相关（p <0.01），而来自放线菌的棕榈酸钠修饰处理中的两个生物标志物与LMW高度线性负相关。 -PAHs残留（p <0.01）。亚油酸钠修饰处理中PAHs（尤其是HMW-PAHs）的去除效率高于棕榈酸钠修饰处理中PAHs（尤其是HMW-PAHs）的去除可能归因于γ-变形杆菌对微生物的特异性富集。分配给PAHs代谢的细菌功能性KEGG直向同源物（KOs）和与苯环裂解相关的功能性C23O和C12O基因均被上调。