Abstract: For the first time, a manganese peroxidase gene mnp (GenBank: MH120207.1) derived from Irpexlacteus (I. lacteus) was optimized and linked to the high-efficiency expression vector pREP without any resistance gene and Gfa gene to construct a prokaryotic-eukaryotic shuttle expression vector pREP-mnp, then electro transformed into Gfa auxotrophic Schizosaccharomyces pombe(S. pombe) to construct biosafety grade S. pombe. The expression of the target protein was verified by SDS-PAGE. The constructed engineered strain expressed MnP extracellularly, and the enzyme activity reached the peak value on the 4th day, which was 17.46 U/L. After fermentation strain screening and nitrogen source optimization, the constructed engineered strain had a significant effect of promoting lignin degradation in synergistic fermentation of corn straw. Added 0.5% urea, 2% (NH4)2SO4, 0.02% Tween-80, 0.5% CaCl2, and 0.3% MnSO4 to corn straw, the final concentration of oxalic acid in the matrix 0.5 mmol/L, S. pombe-pREP-mnp, N. crassa, S. pombe-man, C. utili, 1% Lac, and 0.4% GOD was co-fermented for 3 days. The degradation rates of lignin, hemicellulose and cellulose in corn straw were 60.79%, 27.61%, and 25.49%, respectively, and the true protein content was increased 310.99%.

Key words: manganese peroxidase, Schizosaccharomyces pombe, gene expression, lignin degradation, true protein content