Abstract：Phytic acid is the main form of inositol and phosphorus in plant seeds, because of the body of monogastric animal lack of phytase enzyme, phytate phosphorus forms of phosphorus is difficult for monogastric animal absorption. Phytase has been widely used as feed additives, but the application research in food industry is just beginning. In this study, Aspergillus niger CICC2462 genomic DNA was taken as template, phytase gene(phy) fragments were amplified by PCR, and 5' and 3' homologous arms of saccharifying enzyme gene (glaA) were added on its ends. Ti plasmid of Agrobacterium gene replacement vector pSZHG-phy was constructed. In order to realize the high level expression of phy gene, phy gene replacement glaA gene homologous transformants were screened through A. tumefaciens-mediated transformation of A. niger. Results showed that 4 strains of homologous recombinant transformants were obtained, the rate of homologous recombination was 100%. Spectrophotometer was used to determined its highest fermentation of recombinant transformants, the result was 316.2 U/mL, 20.8 times as much as the starting strain. phy gene could express efficiently in A. niger glucoamylase production strains, and provide a basic data for the further development of food-grade phytase engineering bacteria.
