一株多环芳烃降解菌及其在多种强化体系中降解菲的潜力

A polycyclic aromatic hydrocarbon degrading strain and its potential of degrading phenanthrene in various enhanced systems

摘要:

多环芳烃是一类普遍的环境污染物，因其潜在的环境暴露和对人类健康的危害而备受关注。从石化品污染土壤样品中分离到一株以菲为唯一碳源和能源的中温菌 (15–37 ℃，最佳30 ℃) 菌株CFP312。经菌落和菌体形态观察、生理生化测试和16S rRNA同源性分析鉴定属于莫拉氏菌Moraxella sp.。这是Moraxella属中多环芳烃降解菌种的首次报道。研究表明，当菲浓度为400 mg/L时，在48 h和60 h时，菲的去除率分别为84%和90%，降解速率达到1.21、1.29 mg/(L·h)。在菲的降解过程中，检测到3,4-二氢-3,4-二羟基菲为中间产物。据此推断降解菌通过在菲的3,4位进行双加氧完成其生物降解的第一个关键步骤。在水-有机溶剂两相分配体系、胶束水溶液体系和浊点体系中检测了降解菌对不同的菲强化降解体系的适应性。结果表明，降解菌对不同降解体系都表现出了良好的适应性。另外，降解菌可在泥浆-水体系中快速降解污染土壤中的多环芳烃菲，表明其在环境修复方面具有很大的应用潜力。

关键词:多环芳烃，生物降解，菲，莫拉氏菌，泥浆

Abstract:

Polycyclic aromatic hydrocarbons (PAHs) are a class of common environmental pollutants that pose threats to human health. In this study, a mesophilic bacterial strain CFP312 (grown at 15–37 °C, optimal at 30 °C) was isolated from PAHs-contaminated soil samples. It was identified as Moraxella sp. by morphological observation, physiological and biochemical test, and 16S rRNA gene phylogeny analysis. This is the first reported PAHs degrading strains in Moraxella. Degradation analysis showed that 84% and 90% of the loaded phenanthrene (400 mg/L) were degraded within 48 h and 60 h, and the degradation rates reached 1.21 and 1.29 mg/(L·h), respectively. During the degradation of phenanthrene, phenanthrene-3,4-dihydrodiol was detected as an intermediate. Based on this, it was proposed that double oxygenation at the positions 3 and 4 of phenanthrene was the first step of biodegradation. Adaptability of strain CFP312 to different enhanced phenanthrene-degradation systems was tested in aqueous-organic system, micellar aqueous system, and cloud point system. Strain CFP312 showed good adaptability to different systems. In addition, the bacterium can rapidly degrade the phenanthrene in contaminated soil in slurry-aqueous system, indicating great potential in environmental remediation.

Key words:polycyclic aromatic hydrocarbons, biodegradation, phenanthrene, Moraxella, slurry