COMPARISON OF BIOCHEMICAL PROPERTIES OF RECOMBINANT PHYTASE EXPRESSION IN THE FAVORABLE METHYLOTROPHIC PLATFORMS OF PICHIA PASTORIS AND HANSENULA POLYMORPHA

Abstract

Phytic acid is the dominant form of phosphorous in plant seeds. However, phytic acid cannot beutilized by animals and causes them serious phosphate deficiency. Utilization of phytase as ananimal feed additive can affect liberation of phosphor and its mineral availability. In this study,heterologous expression of the A. niger phyA gene was investigated in the methylotrophic yeastsP. pastoris and H.polymorpha and its expressed active recombinant phytase biochemical andbiophysical properties were studies and compared to native A.niger phytase. The phyA genesequence of A.niger was designed and expression of synthetic genes was highly successfully inactive form in both yeast hosts. Size of the secreted recombinant phytases, due to heavyglycosylation, varied from 50 to 65 KDa. Expressed extracellular recombinant phytase sampleswere purified and biochemical tests on properties demonstrated that both recombinant phytasesamples had similar pH profiles with pH optima determinations of pH 2.5, pH.5.5 as acidphosphatase and optimum temperature of 60 and 50 °C respectively in P. pastoris and H.polymorpha. This study concludes that recombinant P. pastoris and H. polymorpha phytases could fulfil aseries of predefined industrial quality criteria for application as animal feed supplement.