重组大肠杆菌生产脂肪氧合酶的发酵优化

Optimization of fermentation conditions for the lipoxygenase production by Escherichia coli

以本研究室保存的脂肪氧合酶生产菌株重组大肠杆菌Rosetta(DE3)/pre-LOX为研究对象,在摇瓶水平上对培养基、诱导温度、诱导剂浓度、外源添加物进行优化;在3L发酵罐水平上对初始诱导菌体浓度(OD600)进行优化。摇瓶发酵条件下,诱导温度为20℃,当菌体OD600达到0.6,添加1mmol/L诱导剂及0.5%吐温-20,胞外酶活达到8.4U/mL;在3L发酵罐上,诱导温度为20℃,当菌体OD600达到8.0,添加1mmol/L诱导剂及0.5%十二烷基磺酸钠,胞外酶活为8.3U/mL,这是国内外发酵生产脂肪氧合酶的最高水平,对生产实践具有一定的指导意义。

In order to provide the basic data to industrial production and application,we investigate the improvement of productivity of the recombinant lipoxygenase （LOX） through process optimization.The Escherichia coli Rosetta （DE3）/pre-LOX preserved in our lab was used as the LOX producing strain.The induction temperature,inducer concentration,and the type of additives were optimized on a flask scale while the effect of cell concentration at the initial time of the induction was investigated in 3 L fermentater.In the case of flask fermentation,the maximum LOX activity reached 8.4 U/mL when the induction （1 mmol/L inducer and 0.5% （v/v） tween-20） was performed at 20 ℃ and cell density get 0.6 OD600 unit.At the same induction temperature,8.3 U/mL LOX was produced extracellularly in 3 L fermentater under the condition that the initial cell density reached 8 OD600 unit and 0.5% （v/v） sodium dodecyl sulfate was added.The productivity （8.3 U/mL） of the LOX in 3 L fermenter obtained here is higher than ever reported,and the results have guiding significance for industrial production.