Efficient Degradation Of Azo Dye Selection And Degradation Mechanism Of White-rot Fungi

An abundant use of Azo dyes in the textile and paper making industries as well as their residue in environment pose serious hazards to the animals and human beings and even the entire ecosystem. White rot fungi are well known microorganisms for decolorization of a wide range of synthetic dyes due to their non-specific extracellular ligninolytic enzyme system consisting of laccase, manganese peroxidase, and lignin peroxidase. White rot fungi have an ability todegrade toxic compounds having broad substrate specificity, and can metabolize and degrade a lot of chemicals including dyestuff compounds. Lots of research results show that the white-rot fungi play an extremely important role in industrial wastewater treatment, environmental monitoring and other fields.From 11 strains of white rot fungi,1 strain can efficient degradation of azo dye strains, and the strain of the degradation of azo dye degradation condition, the degradation characteristics and degradation mechanism were studied, through the LC - MS on the analysis of the degradation of azo dye intermediate, speculated that goal in the degradation of azo dye degradation of acid chrome blue K can approach, for the strain provides theory basis for further application.This paper screen ones train capable of degrading azo dye from 11 strains of white rot fungi. Study on azo dye, by LC-MS on the analysis of the degradation of azo dye intermediate, speculated that the possible degradation pathway of the degradation of acid chrome blue K, provides theory basis for further application for the strain.Through the liquid shake flask culture found that 11 strains of white rot fungi strains, Versicolor SG0027 has higher decolorizing efficiency on five different structure of azo dyes, and decoloring effect is the most significant of acid chrome blue K. After the optimization of the conditions of the degradation of acid chrome blue K by the Versicolor SG0027, we obtained better conditions were as follows: (1) the culture temperature at 28 ℃, initially pH at 5.5, speed at 150r/min, liquid volume at 30mL/100mL conical flask, inoculums at 2 pieces.(2) According to Plackett-Burman experimental results, we found that culture temperature, inoculums,glucose concentration in the medium, and had a significant effect on the degradation rate of Azo dye. (3) Using response surface methodology for optimizing culture temperature, inoculums,glucose concentration in the medium, to obtain the optimal combination of three conditions were as follows:the culture temperature at 28 ℃,inoculums at 2 pieces,20 g/L glucose concentration in the medium, the culture temperature is the biggest effect on the degradation efficiency. The results of verification show that optimized degradation can reach 96.28% of Versicolor SG0027 on acid chrome blue K rate, the optimization effect is obvious. Existing research results show that, different metal ions, different medium body and different inducer have different effects on degradation decoloring by white rot fungi. This article examines the different metal ions (Zn2+, Ca2+, Na+, Cu2+, Fe3+), different inducer (polysorbate 80, guaiacol, benzyl alcohol), different media (tannic acid, citric acid, oxalic acid) on Versicolor SG0027 degradation decoloring effect of acid chrome blue K.In this paper, the study found that the metal ions Cu2 + inducer twain80 and media tannins for versicolor SG0027 degradation decoloring of acid chrome blue K is more obvious, Different concentrations of metal ions Cu2+ inducer twain80 and media tannins have different effects on Versicolor SG0027 degradation decoloring acid chrome blue K. The decolorization of acid chrome blue K of the degradation process by Versicolor SG0027, White rot fungi have certain adsorption effect on azo dyes, Enzymatic play the main role in degradation pathway.Using the LC-MS analysis of intermediate metabolites of degradation acid chrome blue K by Versicolor SG0027, The results show that the intermediate metabolites produced of the degradation of acid chrome blue K are 4,5-2-2,7-naphthalene disulfonic acid disodium salt(m/z=158.9≈159)and-4-3-hydrazine, hydroxy benzene sulfonic acid anion (m/z=66.9≈67), in the process of degradation of acid chrome blue K,the-C-N=key fracture at first, the-N=N-key fracture at first in metabolic pathway possibly, and then into the middle of other products, the reason may be that laccase produced by Versicolor SG0027 activate different active site of acid chrome blue K.