一组高效喹啉降解复合菌群的构建及其降解特性

Screening and biodegradation characteristics of an efficient quinoline-degrading microbial consortium

摘要:

【背景】喹啉是一种典型的含氮杂环污染物，广泛存在于焦化废水，具有致畸、致癌、致突变作用，易通过水体污染环境。微生物技术因其绿色高效的特点，被认为是喹啉废水污染最有前景的修复手段之一。【目的】筛选得到一组高效喹啉降解复合菌群，实现含喹啉废水的高效工业化处理。【方法】使用逐级递增驯化法从焦化废水厂污泥中筛选出一组高效喹啉降解复合菌群，结合形态学观察并通过酶活测定、底物广谱性研究，完成对该复合菌群的初探。然后将该复合菌群的培养pH、温度、转速、装液量、接菌量、不同浓度外加碳氮源进行单因素优化，结合优化结果以喹啉降解率为目标进行响应面优化，并通过降解动力学研究喹啉对复合菌群降解行为的影响。【结果】分离出可30 h降解1 500 mg/L喹啉的高效复合菌群，可以降解多种含氮杂环化合物；响应面优化结果表明，当pH、温度、转速分别为6.8、30 ℃、200 r/min时，降解率最高达66%；降解动力学分析发现，当喹啉浓度为1 154 mg/L时，比降解率最大高达60.0 mg/(L·h)。【结论】该复合菌群具有高效喹啉降解能力和底物降解广谱性，为微生物高效处理含喹啉废水的工业化处理提供了良好基础。

关键词:喹啉;复合菌群;降解特性;响应面优化;降解动力学

Abstract:

[Background] Quinoline, a typical nitrogen-containing heterocyclic pollutant in coking wastewater, is teratogenic, carcinogenic, and mutagenic, posing a threat to the environment. Microbial technology is environmentally friendly and efficient in the treatment of water polluted by quinoline. [Objective] To screen an efficient quinoline-degrading microbial consortium for the industrial treatment of quinoline-containing wastewater.[Methods] An efficient consortium was screened from the sludge of a coking wastewater plant by incremental stepwise domestication. The morphology was observed and the enzyme activity and substrate spectrum were tested. Then, the pH, temperature, rotational speed, loading volume, inoculum volume, and concentration of added carbon and nitrogen sources for the culture of the microbial consortium were optimized by single factor test. [Results] A consortium which can degrade 1 500 mg/L quinoline in 30 h was isolated. It can degrade a variety of nitrogen-containing heterocyclic compounds. The results of response surface methodology showed that the highest degradation rate of 66% was achieved at pH, temperature, and rotational speed of 6.8, 30 ℃, and 200 r/min, respectively. The degradation kinetic analysis revealed that the maximum specific degradation rate of 60.0 mg/(L·h) was achieved when the quinoline concentration was 1 154 mg/L. [Conclusion] The microbial consortium has a high quinolone-degrading capacity and a broad spectrum of substrates. The findings lay a basis for the industrial treatment of quinoline-containing wastewater by microorganisms.

Key words:quinoline;microbial consortium;degradation characteristics;response surface optimization;degradation kinetics