Screening of Phytase-producing Strain and Cloning of Phytase Gene from the Selected Strain

Abstract:

A strain with relative higher phytase-producing ability, Aspergillus fumigatus WY-2 was screened from soil. The optimal pH and temperature for activity of the phytase from A.fumigatus WY-2 were 5.5 and 55 ℃, respectively. The gene encoding the phytase was amplified from genomic DNA of the strain by PCR, and a 1.5 kb DNA fragment was obtained and then was cloned into vector pMD18-T. The sequencing analysis revealed that the DNA fragment contained a whole open reading frame (ORF) of phytase gene. The phytase gene was 1459 bp in length included with a 61 bp intron and encoded 465 amino acids. A signal peptide encoding 26 amino acids was found at 5′end of the gene. There were 7 potential glycosylation sites in the phytase. The present phytase showed 91% identity in nucleotide sequence and 91% identity in deduced amino acids sequence to the previously reported A.fumigatus ATCC34625 phytase.