Microbial Studies on the Korean Traditional Soju -Part 1. Characteristics of Fungal Amylases Produced by the Isolate from the Native Youngkwang Koji-

우리나라 재래 소주에 관한 미생물학적 연구 -제1보. 영광 토종국에서 분리한 곰팡이의 Amylase 활성-

The most active strain for the amylase activity from the native Youngkwang koji, was isolated and identified as Aspergjllus awamori. The optimal conditions for the production of ${\alpha}-amylase$ and glucoamylase were investigated and the properties of these enzymes were also examined. Maximum yields of ${\alpha}-amylase$ and glucoamylase were obtained at $30^{\circ}C$, pH 5.0 for days. The production of these two enzymes were increased with the addition of maltose, urea, $K_2HPO_4$, $MgSO_4{\cdot}7H_2O$, and $CaCl_2{\cdot}2H_2O$. The activities of these enzymes were maximized at $50^{\circ}C$, $pH\;5{\sim}6$. The heat stabilites of ${\alpha}-amylase$ and glucoamylase were maintained at $50^{\circ}C$ for 20min and 40min, respectively. Also, the addtion of $MgSO_4{\cdot}7H_2O$, $K_2HPO_4$, and $CaCl_2{\cdot}2H_2O$ salt increased the heat stabilities of these enzymes.

영광 토종국에서 분리된 곰팡이중, amylase 생산성이 우수한 Asp. awamori의 ${\alpha}-amylase$, glucoamylase의 생산 및 활성에 대해 밀기울을 기본배지로 하여 배양조건을 검토한 결과, 본 균주에 대한 두 효소의 생산성은 $30^{\circ}C$에서 72시간 배양했을 때 최대에 달하였고 기본배지에 maltose, urea, $MgSO_4{\cdot}7H_2O$, $K_2HPO_4$, $CaCl_2{\cdot}2H_2O$를 첨가했을 때 현저히 증대되었다. 최대효소활성은 pH 5.0 및 $50^{\circ}C$에서 나타났고, $pH\;5.0{\sim}6.0$에서 안정하였으며 $CaCl_2{\cdot}2H_2O$를 첨가하면 pH 안정성이 증가하였다. 열안정성은 $50^{\circ}C$애서 ${\alpha}-amylase$는 20분, glucoamylase는 40분간 열처리 후에도 유지되었고, ${\alpha}-amylase$는 $MgSO_4{\cdot}7H_2O$, $K_2HPO_4$를 glucoamylase는 $CaCl_2{\cdot}2H_2O$를 첨가했을 때 열에 대한 안정성이 증대되었다.