[Expression of phytase gene phyA in Yarrowia lipolytica po1h]

Using the polymmerse chain reaction (PCR), we amplified the phytase gene phyA from Pichia pastoris GS115-phyA in Aspergillus niger NRRL3135 without the signal peptide sequence and intron sequence,. Then, it was cloned into pINA1297 vector to generate a recombinant vector of pINA1297-phyA. pINA1297-phyA was linearized and transformed into Yarrowia lipolytica po1h by the lithium acetate method. The positive transformants were obtained by YNB(casa) and PPB plates, after induced in YM medium at 28 degrees C for 6 day. The activity of the expressed phytase phyA reached 636.23 U/mL. The molecular weight of the enzyme was 130 kDa measured with SDS-PAGE analysis, whereas its molecular size reduced to 51 kDa after deglycosylation which is correspond with theoretical value. The enzymatic analysis of the recombinant phytase phyA revealed its optimal pH and temperature was 5.5 and 55 degrees C, which had high activity after incubated in pH ranged from 2.0 to 8.0 for 1 h. Moreover, its activity remained 86.08% after exposure to 90 degrees C for 10 min. It also was resistant to pepsin or trypsin treatment.