Studies on the Synthesis of Alpha-Amylase and Free Amino Acids by Mutants of Aspergillus Oryzae

Abstract

Increased production of certain organic acids, enzymes, and antibiotics by fungi which can synthesize these substances has been accomplished in many instances by inducing mutations in the parent strains. A family of selected strains of Penicillium chrysogenuin has been produced by Backus and Stauffer (3) who used ultra-violet radiation, X-rays, nitrogen mustard, and other chemicals to produce mutants which can synthesize greater amounts of penicillin than the original strains. Diller et al. (6) produced a mutant of Aspergillus niger, using X-rays, which fermented glucose to citric acid more efficiently than the parent. Raper et al. (10) found that the production of itaconic acid by a mutant of Aspergillus terreus, induced with ultra-violet radiation, was greater than that produced by the parent. In other studies, Nobuyoshi (8) isolated 2 mutants of Aspergillus oryzae, induced with ultraviolet radiation, which surpassed the original strain in amylase activity by 100%, and in protease activity by 50%. Maxwell (7), using ultraviolet radiation, also induced a mutant in A. oryzae which produced more protease than the parent strain. Supersonic sound waves were used by Oda et al. (9) to produce variants in A. oryzae which had greater amylase and protease activity than the parent strains. In this investigation, the amylase-producing potentials of industrially important strains of Aspergillus spp. were studied. Additional studies were made on the amino-acid metabolism of mutants of A. oryzae.