Gene Cloning, Expression and Optimization of Phytase Production in Pichia Pastoris

The phytase coding gene (PhyA) of size 1.3 kb isolated from Aspergillus ficuum NRRL 3135 and cloned in Pichia pastoris strain GS115 as recombinant pPICZ alpha A-phytase was used for phytase production. The extracellular phytase activity after optimization with different co-substrates induction strategy in 4 L fermentor (NBS) increased to 13250 U/ml which is 509 fold increases compared to the wild type. This activity was achieved after inducing GS115/pPICZ alpha A-phytase with methanol along with sorbitol as co-feeding in fed batch fermentation at 20 degrees C. The cloned phytase gene will have a potential to produce the thermostable enzyme which could be used in food industry as animals diets.