Abstract:

Pseudomonas sp. strain LV1, a quinoline-degrading bacterium, was taken as the research object. Firstly, the effects of carbon source on the quinoline degradation performance of strain LV1 were studied, and the results showed that the appropriate addition of sodium acetate could promote quinoline degradation of strain LV1. When the sodium acetate dosage was 1.00g/L, the promotion effect was the most significant. Based on this, a sequencing batch biofilm reactor was successfully started by applying sodium acetate and stepwise increasing quinoline concentration. Then, the strain LV1 was inoculated into the reactor to investigate its effects on the degradation performance of quinoline, and results indicated that the removal rates of quinoline and COD_cr in the effluent were stable at 95.70%±1.25% and 86.49%±0.99%, respectively, after the reactor inoculated with strain LV1 was run for 35d. Compared with uninoculated LV1, the removal rate of quinoline and COD_cr increased by 46% and 33%, respectively, indicating that strain LV1 could enhance the degradation of quinoline in the reactor. Finally, the microbial community structure before and after reactor strengthening was analyzed through the 16s rDNA high-throughput sequencing technology. After inoculation with LV1, the microbial diversity and microbial community structure of the system were significantly changed. Pseudomonadaceae and Comamonadaceae were the core populations that degraded quinoline pollutants in the start-up stage and the bioaugmentation stages. Among them, the relative abundance of Comamonadaceae belonging to Betaproteobacteria increased significantly during the bioaugmentation stage. According to PICRUSt, the relative abundance of the genes encoding aromatic ring lyase, especially the genes encoding nitrogen heterocyclic lyase, was significantly increased in the start-up stage and the bioaugmentation stages, which were conducive to maintaining or enhancing the degradation performance of quinoline.

Key words: quinoline degradation, Pseudomonas sp., sequencing batch biofilm reactor, bioaugmentation, microbial community structure

摘要：

以能够降解喹啉的假单胞菌属细菌LV1为研究对象，首先研究了碳源对菌株LV1喹啉降解性能的影响，结果表明适当添加乙酸钠可以促进菌株LV1的喹啉降解性能，且当乙酸钠添加量为1.00g/L时促进效果最为显著。基于此，采用外施乙酸钠和梯度增加喹啉浓度方式成功启动了序批式生物膜反应器。然后将菌株LV1接种至反应器考察其对反应器喹啉降解性能的影响，结果表明接种LV1的反应器运行35天后出水喹啉和COD_cr去除率分别稳定在95.70%±1.25%和86.49%±0.99%。与未接种LV1相比，强化后反应器喹啉和COD_cr去除率分别提高了近46%和33%，表明菌株LV1能够强化反应器对喹啉的降解。最后通过16s rDNA高通量测序技术分析了反应器强化前后菌群结构的变化，接种LV1后显著改变了系统微生物的种群多样性以及菌群结构，假单胞菌科和丛毛单胞菌科是反应器启动阶段和生物强化阶段降解喹啉污染物的核心种群，其中归属于β-变形杆菌纲丛毛单胞菌科在强化阶段的相对丰度显著增加。根据PICRUSt结果发现挂膜启动和生物强化阶段编码芳香环裂解酶基因特别是编码氮杂环裂解酶基因的相对丰度显著增加，这些均有利于维持或增强反应器的喹啉降解性能。

关键词: 喹啉降解, 假单胞菌属, 序批式生物膜反应器, 生物强化, 微生物群落结构