NY3菌胞外活性小分子对其降解烃效率的影响及作用机理

发布时间：2018-05-01 01:32

本文选题：铜绿假胞单菌NY3 + 有机酸　；参考：《西安建筑科技大学》2017年硕士论文

【摘要】：铜绿假单胞菌NY3是优良的烃降解菌株,除胞内有多种启动烃降解氧化酶外,该菌属有非常丰富的胞外分泌物,除Rha以外其他胞外分泌物对该类菌降解烃的作用鲜有报道。本文从共存有机酸对NY3菌降解烃效率的影响作用出发,通过实验揭示共存有机酸影响铜绿假单胞菌NY3降解烃效率的主要原因,是通过影响该菌的胞外分泌物,尤其是吩嗪类物质的分泌量。研究工作有重要理论和实际应用价值。本论文以NY3菌株为受试菌种,以单一烷烃为降解对象,借助于紫外光谱、气相、飞行质谱和电子顺磁共振等研究手段展开相关工作,获得以下成果:(1)与十六烷为唯一碳源相比,共存戊二酸、丁二酸、丙二酸、乙酸和草酸等均可促进NY3菌对十四烷的降解效率,其中共存戊二酸和草酸促进用作较为显著。除草酸外,其他共存有机酸均可促进NY3菌的生长量。(2)NY3菌生长胞外液均对十四烷有较高的、至少可持续72h的降解转化效率。胞外液对烃的降解效率与NY3菌分泌于其中的两种氧化还原酶(NADH与GSH)和吩嗪类氧化还原活性物密切相关。NY3菌在各生长条件下,均可分泌四种吩嗪物质:1-羟基吩嗪(PHZ)、绿脓菌素(PYO)、吩嗪1-甲酰胺(PCN)、吩嗪1-羧酸(PCA),生长碳源可影响吩嗪类物质的分泌量。(3)共存草酸对NY3菌细胞繁殖能力和细胞降解烃的活性均不利,然而,共存草酸却能明显促进NY3菌对十四烷的降解转化效率。研究表明,共存草酸是通过促进NY3分泌PCA的量而提高烃降解效率的。PCA分泌量与胞外液对十四烷的降解率呈正相关。细胞降解烃的同时,胞外液对烃的降解效率不可忽略。共存草酸可使胞外液对十四烷的降解率约提高28%。草酸共代谢作用可以通过促进NY3菌胞外液中PCA的分泌从而加快胞外液通过自由基机理对十六烷的降解。(4)体外降解实验结果表明,NY3分泌于胞外的4种吩嗪类物质PCA、PYO、PCN、PHZ等均能与胞外氧化还原辅酶NADH和GSH等配合降解十四烷,8h内十四烷的去除率最大可达到48.1%。吩嗪类与辅酶NADH和GSH配合可产生羟基自由基,而胞外液及其吩嗪类对烃的降解是由这些羟基自由基引发的。本文的研究结果为NY3菌修复石油烃污染环境条件优化及其应用奠定理论基础。
[Abstract]:Pseudomonas aeruginosa (NY3) is an excellent hydrocarbon-degrading strain. Except for a variety of activated hydrocarbon degradation oxidase, Pseudomonas aeruginosa has abundant extracellular secretions. The effects of extracellular secretions other than Rha on the degradation of hydrocarbon are rarely reported. Based on the effect of coexisting organic acids on the hydrocarbon degradation efficiency of NY3 bacteria, the main reason for the effect of co-existing organic acids on the hydrocarbon degradation efficiency of Pseudomonas aeruginosa NY3 was revealed through experiments, which was by affecting the extracellular secretion of Pseudomonas aeruginosa. In particular, the amount of phenazine secreted. The research has important theoretical and practical application value. In this paper, the NY3 strain was used as the tested strain, the single alkane was used as the degradation object, and the relative work was carried out by means of ultraviolet spectrum, gas phase, mass spectrometry and electron paramagnetic resonance. The following results were obtained: 1) compared with cetane as the sole carbon source. Coexisting glutaric acid, succinic acid, malonic acid, acetic acid and oxalic acid can promote the degradation efficiency of tetradecane by NY3 bacteria. In addition to oxalic acid, other co-existing organic acids could promote the growth of NY3 strain. The extracellular solution of the strain was higher than that of tetradecane, and the degradation and transformation efficiency of tetradecane was at least 72 hours. The degradation efficiency of hydrocarbon in extracellular solution was closely related to the two redox enzymes (nadh and GSH) secreted by NY3 and phenazine redox activity. Four phenazine substances, 1: 1-hydroxyphenazine, phenazine, phenazine 1-carboxylic acid, phenazine, phenazine and phenazine. However, coexisting oxalic acid can significantly promote the degradation and transformation efficiency of tetradecane by NY3 bacteria. The results showed that coexisting oxalic acid could increase the degradation efficiency of hydrocarbon by increasing the amount of PCA secreted by NY3 and had a positive correlation with the degradation rate of tetradecane in extracellular solution. At the same time, the degradation efficiency of extracellular solution can not be ignored. Coexisting oxalic acid can increase the degradation rate of tetradecane in extracellular solution by about 28%. The co-metabolism of oxalic acid can accelerate the degradation of cetane by promoting the secretion of PCA in extracellular solution of NY3 bacteria, and thus accelerate the degradation of hexadecane by free radical mechanism. The removal rate of tetradecane could reach 48.1% in 8h after the degradation of tetradecane by isozyme with extracellular redox coenzymes (NADH and GSH). Phenazine complexes with coenzymes NADH and GSH can produce hydroxyl radicals, and the degradation of hydrocarbons by extracellular solution and phenazine is initiated by these hydroxyl radicals. The results of this paper lay a theoretical foundation for the optimization and application of NY3 bacteria in remediation of petroleum hydrocarbon pollution.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X172

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