一株偶氮染料甲基橙降解菌的筛

发布时间：2017-12-31 09:46

本文关键词：一株偶氮染料甲基橙降解菌的筛选、鉴定及其脱色条件与机理研究　出处：《南京农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：印染纺织行业不但是水资源消耗大户,而且还是水体污染的重要污染源。其中,偶氮染料是最主要的污染物。目前,国内外大多都采用的物理法和化学法处理染料废水,这两种方法具有成本高,处理不完全会造成二次污染的等缺点。生物法处理染料废水成本低、效率高、产泥少、对环境友好。微生物脱色染料废水的机理主要是吸附、酶降解或者二者的结合,还原酶和氧化酶都会参与到微生物降解的过程中。微生物处理染料废水最终的目的是脱色并解毒偶氮染料及其降解产物。目前对偶氮染料脱色或降解主要集中在酵母、藻类、丝状真菌、细菌、混合菌的研究上,但这些研究有如下不足:(1)酵母、藻类、真菌等对染料的脱色主要体现在吸附作用上,而微生物在死亡之后,细胞破裂,它们吸附的染料又会被释放出来,不能达到彻底去除染料的目的。(2)印染废水的含盐量很高,很多微生物在盐浓度达到一定范围时,生长就会被抑制,从而影响微生物对印染废水的脱色。(3)目前应用于染料降解的菌株虽然具有一定的染料脱色能力,但其脱色效率往往不高,对不同结构偶氮染料的脱色效果往往相差较大,广谱性较差。故本文通过运用微生物学、分子生物学以及生物化学等手段,得到一株能够耐受高盐度且对不同偶氮染料都有脱色效果的菌株,并对细菌降解偶氮染料的条件和机理进行研究,主要结果如下:(1)从长期被偶氮染料废水污染的土壤中分离得到一株对甲基橙具有高效脱色效果的菌株,经鉴定为多粘类芽孢杆菌(Paenibacilluspolymyxa),命名为YP-5。它的细胞形态为长杆状,菌落较小,呈圆形,淡黄色,边缘整齐,菌面凸起,表面有光泽,光滑,湿润,呈半透明粘稠状态,属革兰氏阳性细菌。(2)脱色条件优化的实验表明,pH=6,盐度为1%,装液量是50 mL时,菌株YP-5对甲基橙脱色效果最佳,在30h脱色率达到98.9%。并且该细菌对甲基橙的最大耐受浓度能够达到2000 mg/L,对不同的偶氮染料如酸性橙7、刚果红、活性黑5等都具有一定的脱色效率,也具有一定的广谱性。(3)经过不同的检测及分析手段,FTIR以及LC-MS等,得到了菌株YP-5降解甲基橙的基本路径和产生的4种降解产物,分别为对4-氨基甲基偶氮苯磺酸(4-methyl aminoazobenzene-4-sulfonicacid)、2,4-二氛基甲苯(2,4-Diaminotoluene)、N,N-二甲基对苯二胺(N,N-dimethyl-p-phenylenediamine)、对氨基苯盼(4-aminophenol)。在降解过程中,偶氮还原酶、漆酶、锰过氧化物酶对偶氮染料甲基橙降解起到关键作用。此外,降解后的甲基橙染料废水毒性小于降解前的废水,为实际的农业灌溉提供了基础的实验依据。
[Abstract]:Printing and dyeing textile industry is not only a large consumption of water resources, but also an important source of water pollution. Azo dyes are the most important pollutants. Most of the physical and chemical methods used in the treatment of dyestuff wastewater at home and abroad, these two methods have the disadvantages of high cost, incomplete treatment will cause secondary pollution. Biological treatment of dye wastewater has low cost and high efficiency. The mechanism of microbial decolorization dye wastewater is mainly adsorption, enzymatic degradation or combination of both. Reductase and oxidase are both involved in microbial degradation. The ultimate purpose of microbial treatment of dye wastewater is to decolorize and detoxify azo dyes and their degradation products. Yeast. Algae, filamentous fungi, bacteria, mixed bacteria, but these studies have the following deficiencies: 1) yeast, algae, fungi and other dye decolorization is mainly reflected in adsorption, but after the microbial death. When the cells break down, the dye adsorbed by them will be released again, which can not completely remove the dye. The salt content of printing and dyeing wastewater is very high. Many microorganisms reach a certain range of salt concentration. Growth will be inhibited, thus affecting the microbial decolorization of printing and dyeing wastewater.) although the strain used in dye degradation has a certain ability to decolorize dyes, its decolorization efficiency is often not high. The decolorization effect of azo dyes with different structures often varies greatly, and the broad-spectrum is poor. Therefore, microbiology, molecular biology and biochemistry are used in this paper. A strain with tolerance to high salinity and decolorization of different azo dyes was obtained, and the conditions and mechanism of bacterial degradation of azo dyes were studied. The main results were as follows: (1) A strain with high decolorization effect on methyl orange was isolated from soil contaminated by azo dye wastewater for a long time. It was identified as Paenibacillus polymyxaan, named YP-5. its cell form is long rod shape, the colony is small, it is round and yellowish. The results showed that the optimum decolorization conditions were smooth, smooth, moist, translucent and viscous. The optimum decolorization conditions were Gram-positive bacteria. The results showed that the pH value was 6 and the salinity was 1%. The best decolorization effect of the strain YP-5 on methyl orange was obtained when the volume of liquid was 50 mL. The decolorization rate reached 98.9% at 30 h, and the maximum tolerance concentration of the bacteria to methyl orange was up to 2000 mg / L, and to different azo dyes such as acid orange 7, Congo red. Active black 5 has a certain decolorization efficiency, but also has a certain broad-spectrum.) after different detection and analysis means, such as FTIR and LC-MS. The basic pathway and four degradation products of methyl orange degradation by YP-5 were obtained. 4-aminoazobenzene-4-sulfonicacididine, 4-aminoazobenzene-4-sulfonicacididine, 4-aminomethylazobenzene-4-sulfonicacididine, 4-aminomethylazobenzene-4-sulfonicacididine, 4-Diaminotoluenetrimethylamine (N-dimethyl-p-phenylenediamine), NN-dimethyl-p-phenylenediamine (N-dimethyl-p-phenylenediamine). In the process of degradation, azo reductase, laccase and manganese peroxidase play a key role in the degradation of azo dye methyl orange. The toxicity of the degraded methyl orange dye wastewater is less than that of the pre-degradation wastewater, which provides a basic experimental basis for the actual agricultural irrigation.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172

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