Abstract: The manganese peroxidase gene derived from Irpex lacteus was codon optimized and inserted into pET-28a, and then expressed in E.coli BL21. The recombinant enzyme was purified by nickel affinity chromatography to obtain pure enzyme. Its specific enzyme activity was 24 U/mg and molecular weight was 43 ku. The enzymatic properties showed that the optimum reaction temperature and pH were 40 ℃ and 3.0, and the enzyme had good stability in the range of 20 ℃-50 ℃ and pH 2.5-3.5. Na+, Ca2+and Mg2+ promoted the recombinant enzyme activity at the concentration of 10 mmol/L, respectively. When the added mental ion concentration was 5 mmol/L, other mental ions except Ca2+ could inhibit the recombinant enzyme activity. Fe2+ and Cu2+ could significantly inhibit the recombinant enzyme activity at concentrations of 10, 5 and 1 mmol/L. The enzyme efficiently degraded 35.8% of lignin in corn stover and 27.3% of lignin in bran within 48 h.

Key words: manganese peroxidase, Irpex lacteus, metal ion, lignin degradation