Bacillus 균주가 생산하는 효소를 식품과 동물사료 첨가제로 이용하기 위해서 맥아로부터 단백질 분해능력과 전분 분해능력이 우수한 균주를 분리 동정하여 $Bacillus$ $amyloliquefaciens$ CNL-90으로 명명하였다. 분리된 $B.$ $amyloliquefaciens$ CNL-90이 생산하는 ${alpha}$-amylase의 안정성은 pH는 7, 온도는 $40^{circ}C$, protease의 경우는 pH가 7, 온도는 $50^{circ}C$에서 안정했다. $B.$ $amyloliquefaciens$ CNL-90을 밀기울에 접종하여 고체 배양한 결과 ${alpha}$-amylases의 효소활성은 6일 배양 후 290,000 unit/kg이었고, protease의 효소활성은 310,000 unit/kg으로 나타났다. 밀기울에 고체 배양한 생균수는 배양 6일 후에는 $2.2{ imes}10^9$ CFU/g으로 높았다. 사료 요구율 개선은 $B.$ $amyloliquefaciens$ CNL-90 배양액 0.2% 첨가구가 대조구에 비해서 일당 증체량은 6.66% 높았고, 사료 요구율은 0.05% 효과가 있었다. 이러한 결과는 $B.$ $amyloliquefaciens$ CNL-90이 생산하는 단백질 분해효소와 전분 분해효소는 식품산업 및 가축사료 첨가제 산업에 응용할 수 있는 가능성을 확인하였다.
A bacterium, identified as $Bacillus$ $amyloliquefacies$, CNL-90 using 16S rDNA analysis, was isolated from malt grain. The optimal activities of its ${alpha}$-amylase and protease were observed at pH 6 and $60^{circ}C$, and at pH 6 and $50^{circ}C$, respectively although their activities remained stable at pH 7 and $40^{circ}C$for ${alpha}$-amylase and at pH 7 and $50^{circ}C$ for protease. After solid-state fermentation of $B.$ $amyloliquefacies$, CNL-90 on wheat bran for 72hr or 144hr, the ${alpha}$-amylase and protease activities were 170,000 and 290,000 units/kg, and 290,000 and 310,000 units/kg, respectively. The viable bacterial cell counts were $1.5{ imes}10^9$ CFU/g and $2.2{ imes}10^9$ CFU/g at 72hr and 144hr of the solid-state fermentation, respectively. A feeding trial with a total of 127 piglets was also conducted. The animals were divided into two groups: an experimental group fed with the fermented product (63 piglets) and a control group (64 piglets). The growth rate of the experimental group was 6.66% higher than that of the control group (P<0.05). The results of this study indicate that the ${alpha}$-amylase and protease from $B.$ $amyloliquefacies$, CNL-90 can be used for industrial applications due to their activity in production of carbohydrate hydrolysates.
