Bifidobacterium longum을 고농도 배양하기 위하여 최적 생육 조건을 조사하고 cross-flow filtration으로 생육 저해 대사산물인 lactic acid와 acetic acid를 제거하면서 균체 순환 배양을 사용하였다. 회분 배양에서는 탄소원으로 glucose를 50 g/l 농도로 사용하고 초기 pH 6.5인 경우 생육이 가장 높았다. B. longum을 cross-flow filtration으로 12시간 배양한 결과, 희석속도 $0.31h^{-1}$에서 최대 균체농도에 도달하여 16.4g/l의 건조균체량을 얻었으며 이로써 회분 배양시 보다 약 4배 높은 균체를 생산하였다.
The conditions for production of high cell density of Bifidobacterium longum were investigated and the cross-flow filtration system was used to remove the inhibitory metabolites, lactic acid and acetic acid. The maximum cell growth was observed with glucose as carbon source at the concentration of 50 g/l at $37^{circ}C$ with the initial pH 6.5. When B. longum was cultured in a cross-flow filtration system, the maximum cell growth was observed at a dilution rate(D) of $0.31;h^{-1}$ and the dry cell weight was 16.4 g/l($3.5{ imes}10^{10};cell/ml$), which was about four times higher than that obtained in the batch culture with pH control.
