基于DO-stat流加培养控制的L-异亮氨酸发酵条件优化

Optimization of L-isoleucine Fermentation Conditions Based on DO-stat Feeding Culture Strategy by Brevibacterium lactofermentation

L-异亮氨酸(L-Ile)产生菌代谢流的前期研究报道认为,较低的溶氧浓度有利于L-异亮氨酸的积累.为进一步提高L-异亮氨酸的产量,采用DO-stat流加培养控制方法,分别研究了溶氧浓度20%、30%、35%和40%下乳糖发酵短杆菌发酵液中葡萄糖浓度的变化以及L-异亮氨酸的合成情况.结果表明,当发酵罐中溶氧浓度控制在20%时,L-异亮氨酸的产量为24.3 g L-1,比分批发酵提高了15.7%.其中,生产强度为0.338 g L-1 h-1,底物转化率为12.2%.

The dissolved oxygen（DO） concentration plays a significant role in the accumulation of amino acids during amino acid fermentation process.According to the known study on the metabolic flux of L-isoleucine producing strain,lower DO concentration was considered more desirable for L-isoleucine production.In this study,DO-stat feeding strategy was adopted to increase L-isoleucine production.Changes in glucose concentration and L-isoleucine formation under different DO concentrations,i.e.,20%,30%,35% and 40% were investigated.The result demonstrated that 24.3 g L-1 L-isoleucine with productivity of 0.338 g L-1 h-1 and substrate conversion ratio of 12.2% was achieved when DO concentration was controlled at 20%,which was 15.7% higher than that of batch culture.Fig 3,Tab 1,Ref 25