Recombinant pichia pastoris engineering bacterium and application thereof to preparation of purine

The invention discloses recombinant pichia pastoris and an application thereof to preparation of purine. The recombinant pichia pastoris engineering bacterium is constructed by introducing a gene Rihc-2 shown in SEQ ID NO.1, a gene Hac1 shown in SEQ ID NO.2 and a gene PDI shown in SEQ ID NO.3 into host bacteria. According to the recombinant pichia pastoris and the application thereof to preparation of purine disclosed by the invention, adenosine hydrolase is efficiently expressed in pichia pastoris in a secretory expression manner for the first time, and protein expression enhancing strategiessuch as gene high copy, a resistance recyclable expression vector, HAC1 and PDI gene introduction and the like are combined and applied, so that the production efficiency of recombinase is improved.The strain WC-5 obtained by the invention adopts a fed-batch high-density fermentation method in a 5L fermentation tank, and the protein expression quantity of the adenosine hydrolase is 500mg/L. Thefermentation liquid superna