L. acidophilus KCCM 32820과 P. freudenreichii KCCM 31227의 성장곡선 및 5%와 10% 유청 배지를 고압증기멸균 및 저온살균하여 L. acidophilus KCCM 32820과 P. freudenreichii KCCM 31227을 혼합배양시 생성되는 propionic acid와 acetic acid 양을 측정하였다. L. acidophilus KCCM 32820의 대수기는 $6sim21$시간, P. freudenreichii KCCM 31227의 대수기는 $36sim108$시간으로 나타났다. 혼합배양시 propionic acid의 생성량은 5% 유청 배지보다는 10% 유청 배지에서, 고압증기 멸균보다는 저온살균에서 많은 양이 생성되었다. Propionic acid의 최대 생산량은 10% 유청 배지를 저온살균하였을 때 배양 120시간에 7.88 mg/mL이었다. Acetic acid도 5%보다는 10% 유청 배지에서 높은 생성량을 나타냈고 그 생성량은 배양시간이 경과함에 따라 propionic acid 생성량의 $2:1sim3:1$이었다.
This study was carried out to evaluate the growth characteristics of Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 and the production of propionic and acetic acids in 5% and 10% whey broth by mixed culture of L. acidophilus KCCM 32820 and P. freudenreichii KCCM 31227. Exponential phase of L. acidophilus KCCM 32820 was in the range of $6sim12$ hrs and P. freudenreichii KCCM 31227 was in the range of $36sim108$ hrs. In the mixed culture, production of propionic acid was shown to be greater value in the 10% whey broth than in the 5% whey broth and to be greater value in the low temperature for a long time than in sterilization by autoclave. Maximum production of propionic acid was 8.88 mg/mL in the 10% whey broth fermented at 120hrs. Production of acetic acid was revealed to be greater value in the 10% whey broth than in the 5% whey broth. The production quantity ratio of propionic acid to acetic acid was shown between $2:1sim3:1$ during the fermentation process.
