Expression of the Trichoderma reesei Endoglucanse IV in Pichia pastoris

In this work,the Pichia pastoris expression system was applied to express the T.reesei EGⅣ.The eg4 gene was isolated from rice hull induced T.reesei culture through RT-PCR,and was ligated with the Pichia expression vector pPICZαA,resulting in the recombinant plasmid pPICZαA-eg4.The recombinant plasmid pPICZαA-eg4 was then linearized and transformed into P.pastoris GS115,and the eg4 gene was in frame integrated into the Pichia genome through homologous recombination,resulting the recombinant strain P.pastoris-EGⅣ1.With methanol induction,the recombinant strain P.pastoris-EGⅣ1 expressed and secreated EGⅣ into the culture supernatant with CMC activity of 2.11U/mL.The SDS-PAGE analysis showed that the apparent molecular weight of expressed protein was about 50kD,slightly less than that produced by T.reesei.