降解吡啶复合菌系MD1的筛选、降解特性及代谢途径

Screening,degradation characteristics,and metabolic pathway of an efficient pyridine-degrading bacterial consortium MD1

【目的】为筛选吡啶高效降解复合菌系,促进高浓度吡啶废水的降解。本研究围绕吡啶降解复合菌系的筛选、降解特性及代谢途径,旨在获得吡啶高效降解复合菌系,为高浓度吡啶废水微生物降解及完全矿化提供理论依据和技术支撑。【方法】以吡啶为唯一碳氮源从某农药废水处理系统好氧活性污泥中筛选得到一个吡啶高效降解复合菌系MD1。采用16S rRNA高通量测序技术探究了MD1的群落结构及多样性,通过单因素实验考察了MD1的降解特性,利用气相色谱-质谱联用仪对MD1降解吡啶的代谢产物进行了初步检测与鉴定,推测吡啶可能的降解途径。【结果】结果显示,在温度30℃、pH 8.0、NaCl浓度0.1%的最佳条件下培养72 h,MD1对初始浓度1400 mg/L的吡啶降解率为98.44%±0.27%。在属水平上,MD1主要由副球菌属(Paracoccus sp.)、布鲁氏菌属(unclassified_Brucellaceae)、无色杆菌属(Achromobacter sp.)等组成。由代谢产物检测结果初步推测MD1对吡啶的代谢途径为吡啶→烟酸→6-羟基烟酸→2,5-二羟基吡啶→N-甲酰基马来酰胺酸→马来酰胺酸→马来酸→CO_(2)+H_(2)O。【结论】研究筛选得到一个可高效降解吡啶、降解性能稳定的复合菌系MD1。解析了MD1的微生物组成多样性和群落结构,推测了MD1可能的代谢途径,研究结果丰富了吡啶降解微生物资源。

[Objective]To screen out the bacterial consortium capable of efficiently degrading pyridine and promote the degradation of high-concentration pyridine in wastewater.We screened out a pyridine-degrading bacterial consortium and studied the degradation characteristics and metabolic pathways of the consortium,aiming to provide a theoretical basis and technical support for the microbial degradation and complete mineralization of high-concentration pyridine in wastewater.[Methods]We used pyridine as the only nitrogen source to screen out an efficient pyridine-degrading bacterial consortium MD1 from the aerobic activated sludge and water samples of a pesticide wastewater treatment system.The 16S rRNA high-throughput sequencing was performed to reveal the bacterial species,diversity,and structure of MD1.Single-factor experiments were conducted to study the degradation characteristics of MD1.The metabolites of pyridine degradation by MD1 were initially identified by gas chromatography-mass spectrometry,and the possible degradation pathways of pyridine were deduced.[Results]The degradation rate of MD1 incubated at the optimal conditions of 30℃,pH 8.0,and 0.1%NaCl for 72 h reached 98.44%±0.27%when the initial concentration of pyridine was 1400 mg/L.MD1 was mainly composed of Paracoccus,unclassified_Brucellaceae,and Achromobacter at the genus level.The results of metabolite detection suggested that the possible metabolic pathway of MD1 was pyridine→nicotinic acid→6-hydroxynicotinic acid→2,5-dihydroxypyridine→N-formylmaleamic acid→maleamic acid→maleic acid→CO_(2)+H_(2)O.[Conclusion]This study screened out a bacterial consortium MD1 with stable performance in degrading pyridine.The diversity,structure,and pyridine metabolic pathway of MD1 were analyzed,which enriched the resources of pyridine-degrading microorganisms.