Secretional expression of a Bacillus subtilis xylanase gene in the Basidiomycete Coprinus cinereus

The Bacillus subtilis endo (β-1,4-) D-xylanase structural gene (xyn) was trimmed away from its signal sequence and then fused after the signal sequence of the basidiomycete Pleurotus ostreatus manganese(II) peroxidase cDNA. The resulting modified gene (xyn′) was inserted between the promoter and terminator of two chromosome-integrating, heterologous protein expression vectors. These recombinant plasmids were introduced into protoplasts of the monokaryotic Coprinus cinereus trp1 strain with the C. cinereus TRP1-containing plasmid. One Trp⁺ Xyn⁺ transformant for each of the recombinant plasmids was obtained, which showed a markedly high xylan-degrading activity as compared with the control Trp⁺ transformant.