State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China.
J Appl Microbiol. 2012 Oct;113(4):779-89. doi: 10.1111/j.1365-2672.2012.05386.x. Epub 2012 Jul 25.
To investigate the phenanthrene-degrading abilities of the halophilic Martelella species AD-3 under different conditions and to propose a possible metabolic pathway.
Using HPLC and GC-MS analyses, the phenanthrene-degrading properties of the halophilic strain AD-3 and its metabolites were analysed. This isolate efficiently degraded phenanthrene under multiple conditions characterized by different concentrations of phenanthrene (100-400 mg l(-1) ), a broad range of salinities (0·1-15%) and varying pHs (6·0-10·0). Phenanthrene (200 mg l(-1) ) was completely depleted under 3% salinity and a pH of 9·0 within 6 days. The potential toxicity of phenanthrene and its generated metabolites towards the bacterium Vibrio fischeri was significantly reduced 10 days after the bioassay. On the basis of the identified metabolites, enzyme activities and the utilization of probable intermediates, phenanthrene degradation by strain AD-3 was proposed in two distinct routes. In route I, metabolism of phenanthrene was initiated by the dioxygenation at C-3,4 via 1-hydroxy-2-naphthoic acid, 1-naphthol, salicylic acid and gentisic acid. In route II, phenanthrene was metabolized to 9-phenanthrol and 9,10-phenanthrenequinone. Further study indicated that strain AD-3 exhibited a wide spectrum of substrate utilization including other polycyclic aromatic hydrocarbons (PAHs).
The results suggest that strain AD-3 possesses a high phenanthrene biodegradability and that the degradation occurs via two routes that remarkably reduce toxicity.
To the best of our knowledge, this work presents the first report of phenanthrene degradation by a halophilic PAH-degrading strain via two routes. In the future, the use of halophilic strain AD-3 provides a potential application for efficient PAH-contaminated hypersaline field remediation.
研究嗜盐菌 Martelella 种 AD-3 在不同条件下对菲的降解能力，并提出可能的代谢途径。
采用高效液相色谱和气相色谱-质谱分析，分析了嗜盐菌 AD-3 及其代谢产物对菲的降解特性。该分离株在不同浓度菲（100-400mg/L）、广泛盐度（0.1-15%）和不同 pH 值（6.0-10.0）的多种条件下均能有效降解菲。在 3%盐度和 pH 值为 9.0 的条件下，200mg/L 的菲在 6 天内完全耗尽。在生物测定 10 天后，菲及其生成的代谢物对细菌 Vibrio fischeri 的潜在毒性显著降低。基于鉴定出的代谢物、酶活性和可能中间产物的利用，提出了 AD-3 菌株通过两条不同途径降解菲。在途径 I 中，菲通过 1-羟基-2-萘甲酸、1-萘酚、水杨酸和龙胆酸在 C-3、4 位的双加氧作用进行代谢。在途径 II 中，菲被代谢为 9-菲醇和 9、10-菲醌。进一步的研究表明，AD-3 菌株表现出广泛的底物利用谱，包括其他多环芳烃（PAHs）。
研究结果表明，AD-3 菌株具有较高的菲生物降解能力，且降解途径可显著降低毒性。
据我们所知，这是首次报道嗜盐 PAH 降解菌通过两条途径降解菲。在未来，嗜盐菌株 AD-3 的应用为高效修复高盐度污染场地提供了一种潜在的应用。
