Optimization of Conditions on Laccase Production by Funalia trogii and Degradation of Sunset Yellow by Extracellular Crude Laccase

The effect of composition of medium and culture conditions on the laccase production by Funalia trogii was evaluated,and the degradation of edible synthetic pigment sunset yellow by crude laccase was further studied. The results showed that the optimum culture conditions were as follows:25 g/L corn flour,2 g/L peptone,Cu²⁺ 1.5 mmol/L,1 mmol/L vanillin,culture temperature 30 ℃,initial pH6.0,rotation speed 200 r/min. Under the conditions of fermentation,the activity of laccase from F. trogii after cultured for eight days was(329±12) U/mL,which was 11.96-fold compared to the control. Crude laccase showed high efficiency degradation of sunset yellow and could tolerate high concentration of substrate(800 mg/L). Decolorization efficiency for 50~200 mg/L sunset yellow more than 90%. The addition of laccase mediator could significantly increase the efficiency and rate of sunset yellow decolorization,meanwhile,decrease the inhibition of laccase by high concentration substrates. The addition of kojic acid inhibited the activity of laccase,then the decolorization rate of sunset yellow by laccase was only 7.14%. This study provides a theoretical basis for further development and application of laccase resources in the food industry.