Abstract：Abstract: The cDNA encoding mannanase without the native secretion was cloned by RT-PCR using RNA of the Trichoderma reesei as template. The secreted expression plasmid pPIC9K-man1 of Pichia pastoris was constructed and digested with SacⅠ and transformed into pichia pastoris GS115 by PEG . The positive transformants that integrated man1 gene in their genomes were obtained by PCR technique and determining Mut phenotype. After screen, the recombinant P. pastoris strain RMAN23 was obtained and fermented in large scale 5L fermenter. The recombinant mannanase activity could reach to 470IU/mL .The properties of the recombinant mannanase were characterized.
