Abstract:The study aimed to investigate the decolorization and detoxification abilities of laccase from Pycnoporus sp.SYBC-L3 for azo dyes and optimize decolorization reaction conditions.The effect of different reaction conditions on the decolorization of three azo dyes catalyzed by Lac-L was studied by single factor analysis, and the toxicity change was investigated by comparing the effect of dyes before and after degradations on the germination and the growth of roots and buds of wheat and rice. The results showed that the optimum treatment conditions were as follow： HBT as mediator, reaction temperature at 50 ℃ and pH at 4.0（AR1,RV5R）or 5.0（RB5）, 1 U/mL of laccase dosage, initial dye concentration at 30 mg/L（AR1）or 50 mg/L（RB5、RV5R）. Under the optimized conditions, AR1 and RV5R were almost completely degraded with decolorization rates of 96.1% and 97.8%, while RB5 also had a decolorization rate of 83.8%. Plant toxicological experiments showed that the three azo dyes had no effect on the germination rate of wheat and rice after degraded by laccase, and the inhibition on the growth of germ and root was also reduced.
