Abstract
One hundred and fifty one mutant strains were obtained from the parent strain Aspergillus oryzae MF by ultra-violet ray irradiation. Among those mutants a strain, Asp. oryzae UM-36 which hyperprodued protease, was selected and its morphological characteristics and the production of enzymes protease, ${\alpha}$-amylase, and glucoamylase on wheat bran koji and on soy-sauce koji were studied. The results obtained were as follows 1. The selected mutant showed slower growth and weak sporulation on malt agar and on Czapek agar than the parent strain. 2. The conidiophores of the mutant were generally shorter than those of the parent when grown on malt agar. 3. Sectoring in colonies was not found when grown on malt agar and on Czapek agar. 4. The level of protease production by the mutant was increased approximately 1,4-fold higher on wheat bran koji and 2-fold higher on soysauce koji than by the parent. 5. The production of ${\alpha}$-amylase and glucoamylase by the mutant were also increased as compared with the parent on wheat bran koji and on soy sauce koji. 6. In the case of parent strain and mutant strain, the highest activity of protease appeared after three days in wheat bran medium at $30^{\circ}C$ incubation, but the highest activities of ${\alpha}$-amylase and glucoamylase appeared after two days.
Aspergillus oryzae MF에 자외선(紫外線)을 조사(照射)하여 조사주(照射株) 151주(株)를 분리(分離)하고 이 중(中)에서 protease 생산능(生産能)이 강화(强化)된 변이주(變異株) 1주(株)(Aspergillus oryzae UM-36)를 얻었다. 변이주(變異株)의 특징(特徵)을 조사(調査)하고 밀기울국(麴) 및 간장국(麴)에서의 protease, ${\alpha}$-amylase 및 glucoamylase의 생산(生産)을 검토(檢討)하였다. 그 결과(結果)는 다음과 같다. 1. 변이주(變異株)는 원주(原株)에 비(比)하여 맥아즙한천배지(麥芽汁寒天培地) 및 Czapek 한천배지(寒天培地)에서 생육(生育)이 늦고 포자착생(胞子着生)이 약(弱)하였다. 2. 맥아즙한천배지(麥芽汁寒天培地)에 배양(培養)한 경우(境遇) 변이주(變異株)는 원주(原株)에 비(比)하여 포자병(胞子柄)이 짧았다. 3. 맥아즙한천배지(麥芽汁寒天培地) 및 Czapek한천배지(寒天培地)에 평면배양시(平面培養時) 변이주(變異株)는 sector를 형성(形成)하지 않았으며 안정(安定)된 변이주(變異株)라고 생각되었다. 4. 변이주(變異株)의 protease 생산능(生産能)은 밀기울국(麴)에서 원주(原株)의 약(約) 1.4배(倍), 간장국(麴)에서 원주(原株) 약(約) 2배(倍)이었다. 5. 원주(原株)에 비(比)하여 변이주(變異株)는 밀기울국(麴)이나 간장국(麴)에서 ${\alpha}$-amylase 와 glucoamylase도 많이 생산(生産)하였다. 6. 원주(原株)와 변이주(變異株) 모두 $30^{\circ}C$에서 밀기울국(麴) 배양시(培養時) protease의 최고활성(最高活性)은 배양(培養) 3일후(日後)에 나타났고 ${\alpha}$-amylase와 glucoamylase의 최고활성(最高活性)은 배양(培養) 2일후(日後)에 나타났다.