嗜热复合菌群对偶氮染料的脱色特性及其脱毒

Decolorization and detoxification of the azo dyes by thermophilic microflora

偶氮染料所造成的环境污染问题已成为近年来亟待解决的问题.以前期构建的嗜热偶氮染料降解复合菌群为研究对象,探究其在不同初始p H、培养温度、染料浓度及不同结构偶氮染料的脱色特性,并对不同浓度下染料的降解进行动力学分析;通过紫外-可见光扫描、红外光谱扫描及酶活性变化等分析偶氮染料的生物降解情况.此外,还将通过植物毒理性实验来验证偶氮染料降解后的脱毒情况.研究发现,该复合菌群在初始p H为8、温度为55℃的条件下脱色效果最佳,在含400 mg/L直接黑G的脱色培养基中静置培养48 h后,脱色率高达100%;且对直接黑G具有较高的耐受能力,在3000 mg/L的条件下脱色率仍高达70%;对不同结构的偶氮染料均表现出较好的脱色性能;动力学分析发现其最佳脱色速率与浓度分别为40.5973 mg g^-1 h^-1、484.3376 mg/L.通过紫外-可见光扫描及红外光谱扫描分析发现偶氮染料直接黑G在降解前后化学键及表面官能团发生了明显的变化;酶活性分析发现偶氮染料降解酶在降解后显著提高.此外,植物毒理性实验证明经复合菌群降解后的染料代谢产物对植物的毒性大幅度降低,可能被降解为其他低毒性物质.本研究结果表明该复合菌群具有较好的染料脱色降解性能,这将为偶氮染料的无污染化处理奠定理论基础.(图6表4参43)

Recently,the environmental pollution caused by azo dyes has become an urgent problem.Based on our previous study regarding the degradation of constructed azo dyes by thermophilic microflora,the decolorization characteristics of the azo dyes under different initial p H,temperature,dye concentration,and structures were explored by kinetic analyses.Specifically,the biodegradation of azo dyes were analyzed using a scanning ultraviolet-visible spectrophotometer,an infrared spectral scanner,and enzyme activity changes.In addition,the detoxification of the azo dye was verified by plant toxicity experiments.We found that the optimal decolorization and degradation conditions of the thermophilic microflora were at an initial p H of 8,a temperature of 55℃,and a decolorization rate of 400 mg/L,in which the Direct Black G dye reached 100%after 48 h.Furthermore,the thermophilic microflora had a high tolerance to Direct Black G,despite the decolorization rate reaching 70%at a Direct Black G concentration of 3000 mg/L.In addition,the thermophilic microflora showed a better decolorization performance when using different structures of the azo dyes.Furthermore,the kinetic analysis revealed that the optimal decolorization rate and concentration were 40.5973 mg g-1 h-1 and 484.3376 mg/L,respectively.Through the scanning ultraviolet-visible spectrophotometer and the infrared spectral scanning analysis,the chemical bonds and the surface functional group of the azo dyes were shown to have changed significantly before and after degradation,while the enzyme activity analysis showed that the azo dye-degrading enzyme significantly increased after degradation.Finally,the plant toxicity experiment proved that the toxicity of azo dye metabolites was greatly reduced in plants after being degraded by the thermophilic microflora,which may be due to their transformation into other low-toxic substances.Hence,this work demonstrated that this microflora improved the decolorization and degradation performance of the dye,which can act as a theoretical foundation for the non-polluting treatment of azo dyes.