Pichia pastoris for secretory expression of immunomodulatory peptide Y6 as well as construction method and application of pichia pastoris

The invention discloses pichia pastoris for secretory expression of an immunomodulatory peptide Y6 as well as a construction method and application of the pichia pastoris. According to the invention, codon optimization is carried out on the gene of the immunomodulatory peptide Y6 according to pichia pastoris genetic codon preference, the optimized gene is directionally cloned into a pichia pastoris eukaryotic expression vector pPIC9K to construct a recombinant expression plasmid, the recombinant expression plasmid is transformed into a pichia pastoris GS115 competent cell, and a high-efficiency expression strain is screened; an engineering strain for efficiently expressing the immunomodulatory peptide Y6 is subjected to high-density fermentation culture in a 5L fermentation tank, and fermentation parameters and a process for heterologous expression of the immunomodulatory peptide are optimized. Pichia pastoris serves as an expression host for the first time, a practical heterologous expression technology of t