Immobilization Of Fungal Laccase And Decolorization Of Eriochrome Blue Black R By The Immobilized Laccase

Laccase is a polyphenoloxidase containing coppers,and its application in biological pulping,food processing,wastewater treatment and environment monitoring attracts great attention because the merits of widespread substrate and high catalytice fficiency. However,laccase's practical use is prevented by the shortcoming of high cost and difficult recycling.Enzyme immobilization technology supplies an effective way to reduce the cost and realize the recycling.In order to seek a cheap and efficient way for immobilization of laccase , resin D380 as support and glutaraldehyde (GLU) as cross-linking agent were employed for immobilization of fungal laccase combining adsorption and cross-linking methods, and the properties of the immobilized laccase were also studied. The optimum conditions of the immobilization are as follows: after cross-linking for 2h with 20ml GLU of 0.7%, 1g support were conducted in 2ml diluent laccase solution and 5ml HAC-NaAC buffer solution (pH=4) to adsorb the laccase and react for 6h at 25℃. The recovery of enzyme activity attained finally was 65.94%. The optimum temperature and pH of the immobilized laccase were 20℃and 4, respectively, and about 80% enzyme activity was still hold after preservation at 4℃for 14 days. Michaeils constant of free and immobilized enzymes of 1.207mmol·L-1 and 1.616mmol·L-1 indicated that the affinity of immobilized enzyme to substrate was declined.The quickly developing of textile and printing industries has made dye wastewater treatment a worldwide problem.In the natural conditions,dye pollution is hard to eliminate and achieve the purpose of removing with regular physical,chemical and biological methods.Biological enzymatic becomes one of recent focus for its strong suit of security,clean and efficient in wastewater treatment.Laccase application in wastewater treatment has great value with its ability to degrade variety of phenolic compounds.Fungal laccase immobilized with resin D380 was used to decolorize Eriochrome blue black R, and the influence of the dosage of immobilized laccase, reaction time, pH-value, decolorization rate were explored at normal temperature.When the dosage of immobilized laccase was 0.5g, reaction time-40min and pH-value-5, the decolorization rate of Eriochrome blue black R by immobilized laccase could reach 96.85%.The immobilized laccase could be repeatedly used to decolorize Eriochrome blue black R,and the decolorization rate was still higher than 94% after the 8th use.