DNA ENCODING PHYTASE IN ASPERGILLUS NIGER, RECOMBINANT PLASMID DNA FOR PHYTASE EXPRESSION (VARIANTS), STRAIN-PRODUCERS OF PHYTASE (VARIANTS), METHOD OF PHYTASE PREPARING AND RECOMBINANT PHYTASE Russian patent published in 1998 - IPC

FIELD: molecular biology, genetic engineering, microbiology, biotechnology. SUBSTANCE: invention relates to preparing genome DNA fragment and cDNA encoding phytase in Aspergillus niger and having the definite nucleotide sequences. Recombinant plasmid DNA pFYT3 for phytase expression in Aspergillus has a size 15,3 thousand base pairs and consists of vector PTZ-18 and DNA-fragment operatively bound with promoter of glucoamylase in Aspergillus niger and has gene amds of Aspergillus nidulans as a selective marker. Recombinant plasmid DNA pAF - 2-2S for phytase expression in Aspergillus has a size 13,4 thousand base pairs and consists of vector pUC-19 and pVU-fragment (size is 6,1 thousand base pairs)> The latter has DNA-fragment. Plasmid involves gene amds of Aspergillus nidulans as a selective marker. Strain Aspergillus niger CBS 513.88 is transformed with recombinant plasmid pFYT3 or pAF 2-2S. Strain Aspergillus ficuum NRRL 3135 is transformed with recombinant plasmid pFYT3. Strains are producers of phytase in Aspergillus. Phytae is prepared by culturing cell-producers of phytase of Aspergillus niger or Aspergillus ficuum. Recombinant phytase Aspergillus niger is prepared in Aspergillus ficuum NRRL 3135 or Aspergillus niger CB 513.88 cells by encoding with DNA-fragment. Phytase has the following N-terminal amino acid sequence: Leu-Ala-Val-Pro-Ala-Ser-Arg-Asn-Gln-Ser-Ser-Gly-Asp-Thr-Val-Asp. Its specific activity is 100 U/mg, pH optimum at 5.5 and temperature optimum at 50 C, molecular mass is 85 kDa. Invention can be used in microbiological phytase production. EFFECT: improved method of phytase production. 10 cl, 13 ex, 36 dwg tbl