순창 전통 메주 유래 Lactobacillus brevis SCML 432의 특성 및 통계학적 방법을 활용한 배양 조건 최적화
When used as a starter in the manufacture of Meju, it is expected that the quality of the soup products can be improved. In this study, we isolated Lactobacillus strain having possible safety and food-industrial benefits as a starter. Four hundred and seven isolates were screened from Meju, and chemically characterized for their antibacterial activity against Bacillus cereus, non-productivity of biogenic amine, and hemolysis. Eight of the isolates were selected upon chemical characterization, and their antioxidant and β-glucosidase activity was measured. Finally, we selected, and measured its enzyme activity and antibiotic resistance. Next, we investigated its cell growth, showed maximum biomass of 3.5 g/L after 28 h of culture. The ingredients of the medium to improve biomass were selected using the Plackett-Burman design (PBD) and central composite design (CCD). The results obtained using PBD revealed molasses, yeast extract, and maltose to be significant factors determining the biomass of the L. brevis SCML 432 strain. The CCD was then applied with three variables found from PBD and the optimum values were predicted to be 5.5% molasses, 1.5% yeast extract, and 2.0% maltose, and the maximum biomass was predicted to be 11.2 g/L. Through model verification, we confirmed that the predicted and actual results were similar, with about 3.2-fold improvement in the biomass from 3.5 g/L to 11.3 g/L when compared to that obtained in basal medium. These results suggest that SCML 432 has high potential in the food industry as a starter.