发酵法生产L-异亮氨酸的溶氧控制策略

研究了溶氧对Brewibacterium lactofermentation分批发酵生产L-异亮氨酸（Ile）的影响，提出了前10h恒700d/min以维持溶氧在35％以上，10h后调至600r／min以维持溶氧在15％～20％的两阶段供氧控制模式。与对照相比，获得了较高的产率（0．094g／g）和糖耗速度（4．76/L·h），在较短时间内（52h）获得较高的Ile产量（23．3g／L），比结果最好的单一搅拌转速（600r/min）提高11．6％。生产强度（0．448d/L·h）比恒定搅拌转速（500、600、700、800r/min）控制下的过程分别提高了83．6％、28．7％、44．9％、35．7％。最后采用代谢通量分析对该结果产生的原因进行了定量解释。

Microbial production of L-isoleucine by dissolved oxygen control strategy

The effect of dissolved oxygen （DO） on L-isoleucine production by Brevibacterium lactofermentation was investigated in batch fermentation process. A two-stage DO control strategy was developed, in which the agitation speed was controlled at 700 r/min during in the first 10 h to achieve a DO level up to 35%, and then switched to 600 r/min after 10 h to maintain a DO level at 15% --20 %. A relative high yield （0. 094 g/g） and glucose consumption rate （4.76 g/L·h） were obtained. The high isoleueine production （23.3 g/L） was achieved in a relative short period （52 h）, and it was increased by 11.6o,6 compared to the highest value ofby using single agitation speed （600 r/min）. According to the results in constant agitation speed （500, 600, 700, 800 r/min）, the productivity （0. 448 g/L·h） was increased by 83.6 %, 28.7%, 44.9 %, and 35.7 %, respectively. Finally, the reason for the increase of isoleucine production with the proposed two-stage DO control strategy was quantitatively described in detail by analysis of metabolic flux distribution in metabolic network of isoleucine production by Brevibacterium lactofermentation.