Studies on the fermentation conditions of phytase from Penicillium sp. LQ-7

A Penicillium sp.which can produce phytase with high-activity has been screened and mutated by UV.The best phytase-producing medium is: 3% soluble starch,0.5% peptone,0.5% NH 4NO 3,0.05% MgSO 4·7H 2O,0.05% FeSO 4·7H 2O,0.001% MnSO 4·4H 2O.Primary pH of medium at 6.5,inoculum size at 4%(V/V),fermentation for 72 hours are beneficial to the yield of phytase.The adding of a small quantity of phytate can stimulative the produce of phytase,while excessive phytate will inhibit the reaction.