Development of a novel controller for antimicrobial nisin production, using interaction of microorganisms

为了控制由乳酸菌（LAB）进行的抗菌肽（乳链菌肽）生产过程中的pH，将乳酸乳球菌乳酸亚种（Lactococcus lactis subsp.）lactis（ATCC 11454）的分离方法，该方法既不加碱，也不采用陶瓷膜过滤器和电渗析器等分离系统。将L.乳酸菌与从开菲尔粒中分离的马克斯克鲁维酵母的混合物用于所开发的系统中。乳酸菌乳酸产量之间的相互作用。lactis及其被K.为了利用微生物间的相互作用来维持乳酸链球菌素的高产，研究了L. marxianus的生长动力学和乳酸、乙酸和乳酸链球菌素的产生动力学。研究了乳酸菌。研究了K.马克思主义也被研究过。由于K. marxianus和K.通过改变溶解氧（DO）浓度来控制Marxianus，研制了一种与DO控制耦合的串级pH控制器。结果，pH和乳酸保持在低水平和乳酸链球菌素积累在培养基中的高水平，与其他pH控制策略，如没有pH控制和pH控制通过添加碱的过程相比。

In order to control pH in an antimicrobial peptide (nisin) production process by a lactic acid bacterium (LAB), Lactococcus lactis subsp. lactis (ATCC11454), a novel method was developed, in which neither addition of alkali nor a separation system such as ceramic membrane filter and electrodialyzer was adopted. A mixed culture of L. lactis with Kluyveromyces marxianus, which was isolated from kefir grains, was utilized in the developed system. Interaction between lactate production by L. lactis and its assimilation by K. marxianus was used to control the pH. In order to utilize microbial interaction to maintain high production of nisin, the kinetics of growth and production of lactate, acetate and nisin by L. lactis were investigated. Kinetics of growth and lactic acid consumption of K. marxianus were also investigated. Because pH level in the medium could be controlled by the lactate consumption of K. marxianus and the specific lactate consumption rate of K. marxianus could be controlled by changing the dissolved oxygen (DO) concentration, a cascade pH controller coupled with DO control was newly developed. As a result, pH and lactate were kept at low levels and nisin accumulated in the medium to a high level, compare with other pH control strategies such as processes without pH control and with pH control by addition of alkali.