Method for producing hyaluronic acids with different molecular weights through pichia pastoris gene-regulation fermentation

The invention relates to a novel method for producing hyaluronic acids (HA) with different molecular weights through pichia pastoris gene-regulation fermentation. The method comprises the steps that: recombinant plasmid pGAPZalphaA-szHasA constitutively expressing streptococcus zooepidemicus hyaluronic acid synthase and recombinant plasmid pPICZalphaA-ph20 inducibly expressing recombinant human hyaluronidase are used for converting yeast cells, such that a target strain HAS-PH20 is obtained. Through different gene regulation and induction methods, the yeast engineering strain HAS-PH20 directly produces various hyaluronic acids with different molecular weights through fermentation processes. With the method, the coupling of hyaluronic acid molecular weights and gene regulation methods is realized, and hyaluronic acids with specific molecular weights can be prepared according to requirements.