Study On Decoloration Of Dyestuffs By Laccase

The degradation of different structure dyestuffs including acid,reactive and direct dyesby Laccase (Deniliteâ…¡S)which was from NOVO company was studied in the paper.The optimum decoloration conditions were determined and the effects of differentadditives(such as acid ion, metal ion, and surfactants)were analyzed and discussed. Theresults showed that Laccase had distinct decoloration effects on these dyes, and thatunder optimum reaction conditions the color removal rates of five sorts of dyes(ModerzolBlue FBR, Everacion Blue H-ERD, Moderzol Blue HEGN, Moderacid Green G,Moderacid Yellow A4R)were about 90ï¼…, thereinto, Everacion Blue H-ERD showed thehighest decoloration rate, over 95ï¼…. Based on COD value, except Moderacid Yellow A4RCOD removal rates of other dyes were more than 75ï¼…. According to the optimumdecoloration conditions of ten sorts of dyes, Michaelis-Menten equations were obtainedand dynamics parameters (K_m, V_max) could be calculated, respectively.Among these dyes, the effects of additives on the color removal of dyes (ModeracidGreen G, Reactive Blue K-3R, Direct BlueB2RL) were investigated. The results showeddecoloration was significantly promoted through the addition of Cu²⁺ and Al³⁺, while itwas inactivated with PO₄^3-, CO₃^2-, Fe²⁺ and ion surfactants.Furthermore, the fabric dyed with three sorts of dyes (Moderacid Yellow A4R,Everacion Blue H-ERD, Direct BlueB2RL) were treated with Laccase, and the optimumdecoloration conditions were observed.