Concomitant Production and Utilization of Thermoacidic Phytases from Pichia kudriavzevii FSMP-Y17 in Broilers Feed

Production of phytases from Pichia kudriavzevii FSMP-Y17 yeast was enhanced by optimization of the fermentation variables under submerged fermentation conditions. Maximum 3.67 U/mL of phytases was produced using 2.5% orange peel flour as a substrate, at pH 5.0 and temperature 50°C, by supplementing fermentation medium with 0.2% (wt/vol) galactose as carbon source and 0.2% (wt/vol) ammonium nitrate as a nitrogen source. Addition of sodium phytate to the production medium, however, did not cause any enhancing effect on phytase production by P. kudriavzevii FSMP-Y17 under submerged fermentation. The yeast enzyme purified to near homogeneity in three steps (ammonium sulphate precipitation, anion exchange chromatography and gel filtration) was found showing thermostability (from 40 to 70°C, with highest activity at 55°C) and stable at acidic pH (from 4.0 to 7.0, with highest activity at pH from 5.0 to 6.0). The purified enzyme was added to the diets of the broilers. The diets enriched with yeast phytase showed increased feed intake in the birds, while food conversion rate was lowered. The phytase supplementation caused better phosphorus retention in the birds consequently resulting in enhanced growth of the broilers. The augmented diets also showed improved egg production and egg quality in the hens.