Isolation and characterization of phytase isozymes produced by Aspergillusoryzae

A mutant strain (KL-38) of Aspergillus oryzae was obtained by UV irradiatio n. Phytase activity of KL-38 in molded rice (koji rice) was about 2.7-fold of that obtained from the parent strain (BP-1). Phytase activity of KL-38 i n the submerged culture was similar to that of BP-1. Two types of phytase w ere produced from koji culture: phytase I (Phy I) was produced during incub ation of both koji and submerged cultures, and phytase II (Phy II) was obta ined only from koji culture. Phy II production was increased in KL-38 compa red with BP-1, whereas the production of Phy I was similar for both KL-38 a nd BP-1. This finding indicates that A. oryzae has at least two types of ph ytase isozyme.