• 한국미생물·생명공학회지
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• 제18권3호
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• pp.260-267
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• 1990

분쇄마찰매체 함유 효소반응계에서 순수분리된 glucoamylase 또는 $\alpha$-amylase에 의한 옥수수 생전분의 효소당화 mechanism을 규명코자, 생성된 당조성, SEM을 이용한 전분입자의 구조, 효소흡착량 그리고 amylose 함량 등의 변화를 관찰하였다. 생성당 조성은 분쇄마찰매체 효소반응계에서도 큰 변화없이 glucoamylase의 경우 반응초기부터 glucose가 주로 생성되었고, $\alpha$-amylase의 경우에는 maltopentaose (G5)를 포함한 oligosaccharide(G2-G8)가 주고 생성되었고 약간의 glucose가 포함되었으며, 당조성은 경시적으로 크게 변하지 않았다. SEM으로 전분입자의 구조를 관찰한 결과, 효소를 첨가하지 않을 경우 분쇄마찰매체의 기계적 충격은 전분입자의 구조변화에 큰 영향을 미치지는 못하였고 다만 전분입자를 균열시켰다.

• 미생물학회지
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• 제18권4호
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• pp.161-171
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• 1980

A mutant strain having increased productivity of both enzymes, protease and amylase, was obtained from A. flavus KU 153, isolatd from South Korea for its high protease production by successive ultra-violet light irradiation, Two glucoamylases from the mutant strain selected were purified from wheat branculture by successive salting out, followed by dialysis and column chromatography, and their characteristics were compared with those of the wild strain. Glucoamylase production of the mutant selected was increased about 3.3 times compared with the wild strain, and 2.1 times compared with the parental strain, ${\alpha}-amylase$ activity of the mutant selected was about 2 times hugher than that of the wild strain or the parental strain. Protease and cellulase productivities of the muant selected were all alike compared with those of the highly proteolytic mutant, the parental strain. Therefore, it was considered that the back mutation on the protease production did not occurred in the formation process of the glucoamylase producing mutant. Total activities of glucoamylase I and II from the mutant selected were 2.86 and 3.65 times higher compared with those from the wild strain, respectively. Considering the optimal pH-thermal stability and Km-Vmax value of glucoamylase I and II from both strains, wild and mutant, it was deduced that the characteristics of glucoamylase I and II from the wild strain did not altered during the mutation process. Therefore, it was concluded that the selected mutant did not induce the formation of another glucoamylase isozyme, or the changes in the characteristics of the glucoamylase, but induce the productivity of the same glucoamylase I and II by the action of regulatory gene.