Highly Effective Expression of Aspergillus niger Endo-β-1,4-glucanase in Pichia pastoris

The gene encoding endo-β-1,4-glucanaseⅠ from Aspergillus niger L3 was isolated with RT-PCR.egⅠ was eliminated its native signal peptide by PCR and inserted into the pPIC9K vector of Pichia pastoris in the reading frame with α-factor secreting signal peptide sequence to construct the recombinant plasmid pPIC9k-egⅠ.The recombinant plasmid pPIC9k-egⅠ was transformed into P.pastoris GS115 with electroporation.Two of recombinant P.pastoris stains 1 and 5 were obtained by screen with MM,MD,CMC-Na and G418 plates and the activity of recombinant EGⅠ could reach to 1 456 U/mL and 1 928 U/mL,respectively.The optimal temperature for the recombinant EGⅠ was 70 ℃ and the optimal pH was 5.0.