earticle

영어

Leuconostoc citreum is the major lactic acid bacteria growing at an initial phase of kimchi fermentation. It grows fast at both aerobic and anaerobic conditions producing CO2, mannitol and dextran. In this study, high cell density culture of L. citreum was conducted in a fermentor equipped with an internal ceramic filtration system. The filter material was porous ceramic with pore size of 0.1 μm. The filter module consisted of 20 vertical cylindrical filter rods with inner diameter, outer diameter, and height of 6, 8, and 65 mm, respectively, and an upper frame of stainless steel. The total surface area of the filter module was ca. 330 cm2. The filter module was installed inside a 2.5-L jar fermentor. After 6 h of batch mode, filtration operation was started by feeding medium containing glucose, fructose, and yeast extract and at the same time by removing broth through the filter module. By using the internal filtration system, optical density at 660 nm increased to 70, which was 10 times higher than that in batch culture. The main co-products were mannitol and D-lactic acid. Mannitol and D-lactic acid concentrations increased to ca. 80 g/L and 40 g/L, respectively, by feeding fresh medium.