Screening And Studying On Decolorization Properties Of Decolorizing Microbial Strain

With the development of science and technology,we also pay more attention to the protection of the environment,including the rational utilization of water resources.The textile industry water is one of important reasons of environmental pollution.The hazard of dyeing wastewater is very large.Dyeing wastewater with more synthetic dyes,which causes a large amount of textile wastewater and affect the quality of water.Discharge of raw sewage influences the growth of plants,animals,and people health directly or indirectly.Therefore,the suitable treatment of wastewater is the key issues of conservation,which includes chemical methods,physical methods,and biological methods.However the methods of chemical treatment may produce secondary pollution.At present,the use of biological treatment have been made great progress,and we should find out the efficient microbial strain of decolorization.Biological treatment methods of dye wastewater are more economical,which can not produce secondary pollution,and have been widely used in wastewater treatment.The experiment used the existing and laboratory strains,and studies on whether there was a certain effect on the treatment of dye wastewater.Screen degradation strain from them,and take the strain as the research object,then study on the characteristics of the strain,and decolorization conditions were optimized by response surface,finally studied on the effect of fixed before and after and gave an simple analysis on the decolorization mechanism.The laboratory have Candida tropicalis B21,Candida tropicalis KN2,Candida lipolytica B16 and Candida rugosa B27,Pseudomonas fluorescens A23,Pseudomonas convex type A2,N2,L1,K4 and N1,with four kinds of azo dyes.First choose an azo dye,acid red 3G to screen decolorizing strain,and screen them by point method.The research showed that the N2,Pseudomonas fluorescens A23 and Pseudomonas convex type A2 do not have the capacity of decolorization,by contrast,B16 was well.It was followed by K4,N1,L1,B21,B27.Then used quantitative analysis to determine the decolorization power.The growth characteristic and culture conditions of B16 were also studied.Optimum conditions are temperature at 25?,at speed of 180r/min,yeast extract 30g/L,use glucose 40g/L as carbon source and the optimal p H is 6.After 15 h,the growth of B16 was in the logarithmic phase,and after 24 h was to the stable phase.Studied on decolorization condition,the decolorization of acid red 3G was only about80.16%,the dye decoloration rate of B16 could reach 97.5% in the optimum operation conditions.Candida lipolytica with efficient decolorization of acid red 3G was screened,an experimental design based on the response surface method was applied to find the optimal conditions.theoptimum dye decolorizing activity of the culture was at the speed of 160r/min,glucose(21g/L),yeast extract(10g/L),Mg2+(20mmol/L),Cu2+(9.5mg/L),initial dye concentration(400mg/L)and the temperature(29.6?)with inoculum size of 3%.But when it used to Reactive Black 5,Direct Black 38,and Reactive Blue 4,the decolorization rate was fairly low.Candida lipolytica B16 was immobilized.After immobilized,the influence of temperature and p H to decolorization was smaller than the free,the salt tolerance of immobilized strains was better than the free.Finally by UV,to determine the metabolites of B16 by FTIR.Then Candida lipolytica without extracellular proteins was determined by SDS-PAGE analysis,intracellular substances may have the properties of decolorization.Then gave an simple analysis on the decolorization mechanism.