유산균 발효에 관한 동력학적 연구(제2보) 발효에 미치는 온도의 영향

KINETIC STUDIES OF LACTIC ACID FERMENTATION(PART 2) INFLUENCE OF TEMPERATURE ON FERMENTATION

유산균 식료공법에서 중요한 위치를 차지하는 L. bulgaricus의 배양온도에 의한 산소 효과 및 열역학적 고찰을 요약하면 다음과 같다. 1) L. bulgaricus를 20시간 배양시 균체는 최고농도에 달했고 배양온도 $39^{\circ}C,\;42^{\circ}C\;and\;45^{\circ}C$에서 각각 2.3UOD/ml, 2.6UOD/ml, 2.8UOD/ml로 나타났다. 2) 배양 30시간때 포도당 잔량은 배양온도 $39^{\circ}C,\;42^{\circ}C\;and\;45^{\circ}C$에서 각각 18.3g/l, 15.0g/l, 10.0g/l이었다. 3) 최대비증식속도는 배양온도, $39^{\circ}C,\;42^{\circ}C\;and\;45^{\circ}C$에서 각각 $0.42hr^{-1},\;0.48hr^{-1},\;0.58hr^{-1}$이었고 Saturation constant는 4.57mg/ml, 5.6mg/ml, 6.627mg/ml이었다. 5) 활성화 energy는 9,220cal/mol 배양온도의 변화에 따른 평균치로 활성화 entropy는 $-31.74cal/^{\circ}Kmol$, 반응열은 9,845cal/mol free energy는 19,800cal/mol이었다.

To know the influence of temperature on the fermentation process, a strain of Lactobacillus bulgarius was experimentally cultured three different temperature conditions of $39^{\circ}C,\;42^{\circ}C\;and\;45^{\circ}C$, pH 5.8 and mechanical agitation of 500rpm. During 20 hour's fermentation, the microbial growth attained the maximum concentration under the conditions mentioned above. However, the culturing conditions resulted different outcomes in terms of maximum concentration of the microbes and the residual concentration of substrate. Among the three temperature conditions, the fermentation at $45^{\circ}C$ was most effective and the maximum specific growth temperature conditions, the fermentation at $45^{\circ}C$ was most effective and the maximum specific growth rate was 0.58/hr. Activation energy deduced from the Arrhenius equation was 9,220cal/mole and entropy was $-33.74\;cal/^{\circ}K$ mole. Activation enthalpy was 9,845 cal/mole and free energy was 19,800 cal/mole.