Influence of growth conditions on the nisin production of bioengineered Lactococcus lactis strains
Influence of growth conditions on the nisin production of bioengineered Lactococcus lactis strains
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DOI：
10.1007/s10295-008-0517-4
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发表时间：
2009-01
影响因子：
3.4
通讯作者：
Ö. Şimşek;A. Çon;N. Akkoç;P. Saris;M. Akçelik
中科院分区：
文献类型：
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作者：
Ö. Şimşek;A. Çon;N. Akkoç;P. Saris;M. Akçelik
以乳酸乳球菌（Lactococcus lactisLL 27）为出发菌株，研究了乳酸链球菌素（Nisin）生物合成免疫（nisFEG）和/或调控（nisRK）基因工程菌（LAC 338、LAC 339和LAC 340）在pH控制和非pH控制条件下分批发酵生产Nisin的效果。优化研究表明，果糖和酵母提取物产生最高的乳酸链球菌肽的活性。菌株LAC 338、LAC 339和LAC 340产生的乳链菌肽分别比野生型多24%、45%和44%。lactisLL 27孵育12小时后。然而，在发酵后期，观察到LAC 339和LL 27的乳酸链球菌素产量急剧下降，而LAC 340和LAC 338菌株的乳酸链球菌素高水平可以维持更长时间。很明显，增加乳链菌肽生产菌中调节基因和免疫基因的拷贝数，延缓了发酵后期乳链菌肽的损失。
Nisin production of three bioengineered strains, (LAC338, LAC339 and LAC340) with immunity (nisFEG) and/or regulation (nisRK) genes of nisin biosynthesis on plasmids in theLactococcus lactisLL27 nisin producer, was evaluated under pH-controlled and pH-uncontrolled batch fermentations. Optimization studies showed that fructose and yeast extract yielded the highest nisin activity. The strains LAC338, LAC339, and LAC340 produced 24, 45, and 44% more nisin, respectively, than wild-typeL. lactisLL27 after 12-h incubation. However, sharp decreases in the yield of nisin were observed at the late phase of fermentation with LAC339 and LL27 in contrast to LAC340 and LAC338 strains for which the high level of nisin could be maintained longer. Obviously, increasing the copy number of the regulation genes together with immunity genes in the nisin producers retarded the loss of nisin in the late phase of the fermentation.