Screening of Koji Mold with Hydrolytic Activity on γ-Poly Glutamic Acid

Abstract

The Aspergillus oryzae N-2 which was isolated from 26 commercial Koji starters f or miso and soy sause produced a lot of PGAase which hydrolyzed γ-poly glutamic ac After solid fermentation of A. oryzae N-2 with wheat bran for 3 days, the crude enzyme was extracted and fractionated by ammonium sulfate (60-95% saturation). The partial ly purified enzyme was obtained by dialysis of the fraction against tap water. The optimum temperature and pH of the enzyme were 40°C and 4.5-5.0, respectively, using γ-poly Lglutamic acid as a substrate. The enzyme cleavedgb γ-poly L-glutamic acid signifi cautly and γ-poly D, L-glutamic acid partially. γ-Poly D-glutamic acid was, however, not hydrolyzed. hydrolyzed. γ-poly L-glutamic acid as a hydrolyzate determined by paper chromatography.