Raw starch-digestive glucoamylase productivity of protease-less mutant from Aspergillus awamori var. kawachi.

Abstract

Mutation experiments were performed to decrease the protease productivity of Aspergillus awamori var. kawachi using ultraviolet light and TV-methyl-TV'-nitro-TV-nitrosoguanidine. The selected mutant HF-15 showed reductions in protease productivity of 93%, 84% and 50% in solid wheat bran culture, shaking MediumB and wheat bran cultures, respectively, as compared with the parent. Protease-less mutant HF-15 failed to produce a-mannosidase, and iV-acetyl-/?-Dglucosaminidase productivity decreased by 35%. Mutant HF-15 specifically produced a high amount of raw starch-adsorbable and raw starch-digestive glucoamylase similar to GAI under all tested cultural conditions. Onthe contrary, high protease-producing mutant HF-10 produced a glucoamylase with very limited adsorption and digestion capacity on raw corn starch, and lower hydrolysis toward gelatinized potato starch and glycogen that was similar to GAV.

Optimization of extraction and purification of glucoamylase produced by Aspergillus awamori in solid-state fermentation

“…Many other reports have also mentioned that glucoamylase of Aspergillus sp. exists in two to four isoforms, which vary from species to species [15].…”

Enzymes of the Genus Aspergillus

“…kawachi by protease or glycosidase. A protease-negative mutant of this organism produced but one form of amyloglucosidase (Hayashida and Flor, 1981). Four forms of the enzyme showed different susceptibilities to two proteases (Paszczynski et ai., 1985) in the culture medium of A. niger C. It has been suggested that these two proteases may regulate amyloglucosidase activity and heterogeneity.…”

Production and Characteristics of Raw-Starch-Digesting α-Amylase from a Protease-Negative Aspergillus ficum Mutant

“…We further showed that the protease-negative, glycosidase-negative mutant strain HF-15 of A. awamori var. kawachi produced only raw-starch-digesting glucoamylase GA 0 (MW 250,000; type A) under any conditions of submerged or solid culture (3,5,6). On the basis of these results with glucoamylase, we expected the presence of raw-starch-digesting a-amylase from fungi and tried to isolate the protease-negative mutant that could produce a high amount of a raw-starchadsorbable, raw-starch-digesting a-amylase.…”