| 摘要 |
PURPOSE:To increase microbial cell temperature in a culture vessel and enable enhancement of production efficiency of nisin produced by lactic acid bacteria by producing the nisin while continuously taking out the nisin from a culture solution using a membrane such as an ultrafiltration membrane. CONSTITUTION:Culturing of lactic acid bacteria belonging to the genus Lactococcus is carried out in an obligate anaerobic state in a culture vessel using a culture medium containing saccharides such as glucose, ammonium chloride, etc., as a nitrogen source and a nutrient source such as an inorganic salt. When the microbial cell concentration attains the latter period of logarithmic growth phase, a prescribed amount of the culture solution is taken out and fed to an ultrafiltration membrane such as polyacrylonitrile or a filtration module such as precise filtration and divided into a solution containing the microbial cells and a solution without containing the microbial cells. The solution containing the microbial cells is further returned to the culture solution and the solution without containing the microbial cells is taken out. A fresh liquid culture medium in the same liquid volume as that of the taken out solution is fed into the culture vessel. The aforementioned operation is continuously performed to enhance the microbial cell temperature in the culture vessel. The resultant nisin is then recovered from the taken out solution. Thereby, the nisin can be industrially produced with ultrahigh productivity. |
