Abstract: The yeast cell surface display vector pyd1 MnP was transformed into EBY100 by LiAC method. The MnP protein was successfully anchored on the surface of yeast cells by SDS-PAGE and immunofluorescence, and the transformant was induced to produce manganese peroxidase activity in vitro. It can provide excellent microbial resources for the degradation of azo dye wastewater. The enzyme activity was determined by 2,6-dimethoxyphenol (DMP) method, and the effects of different culture time, temperature, pH, carbon source, nitrogen source and concentration of carbon and nitrogen source on enzyme activity were determined. The enzyme was immobilized with sodium alginate. The optimal culture time and temperature of the immobilized transformant PM-2 were 60 h and 40 ℃. The optimal pH was 4.5, the optimal carbon source was galactose, the optimal nitrogen source was YNB, the carbon source concentration was 0.02 g/mL, and the nitrogen source concentration was 0.0072 g/mL. The adsorption performance of methyl orange simulated wastewater was studied by sodium alginate immobilization. The adsorption process accords with the quasi second order equation, and the fitting effect is better with Freundlich isotherm adsorption equation. The successfully anchored transformant PM-2 had the ability to produce manganese peroxidase, which can play a role in the biodegradation of azo dyes.

Key words: surface display, manganese peroxidase, immunofluorescence, immobilization, methyl orange