Construction of a Pichia pastoris recombinant strain capable of over-expressing phytase and endoglucanase

Abstract

Both phytase and endoglucanase are additives in feed for mono-gastric animal known for their effects. Recombinant vector pPICZalpha-EG was constructed and transformed to GS115-phyA, a Pichia pastoris strain that had integrated with phytase gene, generating GS115-phyA-EG. Both phytase and endoglucanase activities in the supernatant were determined after methanol induction of GS115-phyA-EG. Phytase and endoglucanase activity reached 39.4% and 56.2% activity compared to GS115-phyA and GS115-EG, respectively. Properties of the mixed enzyme suggest that the optimal temperature and pH value be 55 degrees C and 5.5 respectively. Both phytase and endoglucanase showed greater than 80% activity across temperature ranges 45 degrees C to 55 degrees C and pH ranges 4.5 to 5.5. Expressing more than one enzyme in one system could save time and money during induced expression, and the mixed enzyme might apply for treating forge before feeding with poultry.