Graduate School of Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Environ Sci Pollut Res Int. 2016 Aug;23(16):16609-19. doi: 10.1007/s11356-016-6829-4. Epub 2016 May 14.
Bacterial strain YC-RL4, capable of utilizing phthalic acid esters (PAEs) as the sole carbon source for growth, was isolated from petroleum-contaminated soil. Strain YC-RL4 was identified as Mycobacterium sp. by 16S rRNA gene analysis and Biolog tests. Mycobacterium sp. YC-RL4 could rapidly degrade dibutyl phthalate (DBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), dicyclohexyl phthalate (DCHP), and di-(2-ethylhexyl) phthalate (DEHP) under both individual and mixed conditions, and all the degradation rates were above 85.0 % within 5 days. The effects of environmental factors which might affect the degrading process were optimized as 30 °C and pH 8.0. The DEHP metabolites were detected by HPLC-MS and the degradation pathway was deduced tentatively. DEHP was transformed into phthalic acid (PA) via mono (2-ethylhexyl) phthalate (MEHP) and PA was further utilized for growth via benzoic acid (BA) degradation pathway. Cell surface hydrophobicity (CSH) assays illuminated that the strain YC-RL4 was of higher hydrophobicity while grown on DEHP and CSH increased with the higher DEHP concentration. The degradation rates of DEHP by strain YC-RL4 in different environmental samples was around 62.0 to 83.3 % and strain YC-RL4 survived well in the soil sample. These results suggested that the strain YC-RL4 could be used as a potential and efficient PAE degrader for the bioremediation of contaminated sites.
一株能够以邻苯二甲酸酯（PAEs）为唯一碳源生长的细菌菌株 YC-RL4 从石油污染土壤中分离得到。通过 16S rRNA 基因分析和 Biolog 测试，菌株 YC-RL4 被鉴定为分枝杆菌属。分枝杆菌属 YC-RL4 能够在单一和混合条件下快速降解邻苯二甲酸二丁酯（DBP）、邻苯二甲酸二乙酯（DEP）、邻苯二甲酸二甲酯（DMP）、邻苯二甲酸二环己酯（DCHP）和邻苯二甲酸二（2-乙基己基）酯（DEHP），在 5 天内所有降解率均高于 85.0%。优化了可能影响降解过程的环境因素，最佳条件为 30°C 和 pH 8.0。通过高效液相色谱-质谱（HPLC-MS）检测到 DEHP 的代谢产物，并推测出降解途径。DEHP 通过单（2-乙基己基）邻苯二甲酸酯（MEHP）转化为邻苯二甲酸（PA），PA 进一步通过苯甲酸（BA）降解途径被利用。细胞表面疏水性（CSH）测定表明，菌株 YC-RL4 在 DEHP 上生长时具有较高的疏水性，并且随着 DEHP 浓度的增加，CSH 增加。菌株 YC-RL4 在不同环境样品中对 DEHP 的降解率约为 62.0%至 83.3%，且在土壤样品中仍能良好存活。这些结果表明，该菌株 YC-RL4 可作为一种潜在的、高效的 PAE 降解菌，用于污染场地的生物修复。
