Department of Biology, Shantou University, Shantou, Guangdong 515063, China.
Department of Biology, Shantou University, Shantou, Guangdong 515063, China; School of Life Sciences, Huizhou University, Huizhou 510607, China.
J Hazard Mater. 2024 Mar 5;465:133045. doi: 10.1016/j.jhazmat.2023.133045. Epub 2023 Nov 24.
Various persistent organic pollutants (POPs) including estrogens are often enriched in mangrove regions. This research investigated the estrogens pollution levels in six mangroves located in the Southern China. The estrogen levels were found to be in the range of 5.3-24.9 ng/g dry weight, suggesting that these mangroves had been seriously contaminated. The bacterial communities under estrogen stress were further enriched by supplementing 17β-estradiol (E2) as the sole carbon source. The enriched bacterial communities showed an excellent E2 degradation capacity > 95 %. These communities were able to transform E2 into estrone (E1), 4-hydroxy-estrone, and keto-estrone, etc. 16 S rDNA sequencing and metagenomics analysis revealed that bacterial taxa Oleiagrimonas, Pseudomonas, Terrimonas, and Nitratireductor etc. were the main contributors to estrogen degradation. Moreover, the genes involved in E2 degradation were enriched in the microbial communities, including the genes encoding 17β-hydroxysteroid dehydrogenase, estrone 4-hydroxylase, etc. Finally, the analyses of functional genes and binning genomes demonstrated that E2 was degraded by bacterial communities via dehydrogenation into E1 by 17β-hydroxysteroid dehydrogenase. E1 was then catabolically converted to 3aα-H-4α(3'-propanoate)- 7aβ-methylhexahydro-1,5-indanedione via 4,5-seco pathway. Alternatively, E1 could also be hydroxylated to keto-estrone, followed by B-ring cleavage. This study provides novel insights into the biodegradation of E2 by the bacterial communities in estrogen-contaminated mangroves.
各种持久性有机污染物（POPs），包括雌激素，通常在红树林地区富集。本研究调查了中国南方六个红树林地区的雌激素污染水平。研究发现，这些红树林地区的雌激素水平在 5.3-24.9ng/g 干重范围内，表明这些红树林地区已经受到严重污染。通过补充 17β-雌二醇（E2）作为唯一的碳源，进一步富集了受雌激素胁迫的细菌群落。富集的细菌群落表现出出色的 E2 降解能力，>95%。这些群落能够将 E2 转化为雌酮（E1）、4-羟基雌酮和酮雌酮等。16S rDNA 测序和宏基因组分析表明，细菌类群 Oleiagrimonas、Pseudomonas、Terrimonas 和 Nitratireductor 等是雌激素降解的主要贡献者。此外，参与 E2 降解的基因在微生物群落中得到了富集，包括编码 17β-羟甾脱氢酶、雌酮 4-羟化酶等的基因。最后，功能基因和 binning 基因组分析表明，细菌群落通过脱氢作用将 E2 降解为 17β-羟甾脱氢酶产生的 E1。E1 然后通过 4,5-裂环途径转化为 3aα-H-4α（3'-丙酸盐）-7aβ-甲基六氢-1,5-茚二酮。或者，E1 也可以被羟化为酮雌酮，然后进行 B 环裂解。本研究为受雌激素污染的红树林中细菌群落对 E2 的生物降解提供了新的见解。
