Abstract:
Poultry industry is one of the industries which is growing at an exponential rate due to an increased demand and production of broiler chicken by the export markets and local consumers. To balance the amount of phosphorus in animals, the poultry diets are mainly supplemented with seed-based components that store phosphorus in phytic acid form. Phytic acid is indigestible by many animals and it usually makes complexes with other ions like calcium and proteins and as a result hampers their absorption in the animal body. For that matter, phytase enzyme is added in the poultry feed to increase the bioavailability and absorption of phosphorus and other vital ions. This study was conducted to check the potential of local strains of Aspergillus species for the production of phytase enzyme and identify high yielding strains for a more environmentally friendly source of the enzyme. In this study, 20 samples were taken from different cities of Pakistan for the screening of phytase producing fungi on phytase specific screening media. The selected strains were subjected to ITS based molecular identification and were identified as Aspergillus niger and Aspergillus flavus.The fungal cultures were then undertaken submerged fermentation to calculate the total units of enzyme produced. In order to achieve maximum enzyme production, various cultural parameters were optimised, and best units of enzyme were produced with glucose as carbon source, ammonium nitrate as nitrogen source, 120 hours incubation time, 30̊C incubation temperature and 5.5 pH of the fermentation media. Different enzyme units were produced by different strains of Aspergillus species. Aspergillus niger strain N gave maximum units (25 U/ml) of phytase followed by Aspergillus niger strain B4 which gave
19.4 U/ml enzyme. Aspergillus flavus strain AF yielded 7.5 U/ml phytase whereas strain G1 produced 16.36 U/ml phytase through submerged fermentation under optimsed conditions.
