【摘要】 在培养重组大肠杆菌的过程中,乙酸的产生会抑制细菌的生长,也不利于重组蛋白的表达。研究了补料培养重组大肠杆菌过程中,应用脉冲补料方式时溶氧信号的响应特征来辩识是否产生乙酸。当大肠杆菌以0.1h?1的比生长速率生长时,补料过程中发酵液的乙酸含量很低,溶氧pO2的响应信号随脉冲补料而振荡。而在诱导表达重组人表皮生长因子时,大肠杆菌的呼吸能力下降,过量补入的葡萄糖使重组菌产生大量的乙酸,同时pO2的响应信号失去振荡的特征。根据pO2响应信号的特征反馈控制葡萄糖的流加速率,有效地避免了重组蛋白表达过程中乙酸的产生,实现了重组大肠杆菌的高密度培养,菌体干重达到48g?L?1,重组人表皮生长因子的表达水平提高了45%。更多还原

【Abstract】 Accumulation of acetate can inhibit cell growth and reduce recombinant protein production during cultivation of Escherichia coli. Relations between the oscillation of the dissolved oxygen response signal and pulses in feed rate in fed-batch cultivation of recombinant E. coli were characterized. The dissolved oxygen response signal was used to detect the acetate production in pulsed fed-batch cultivation of E. coli. In fed-batch cultivation with glucose-limited growth at specific growth rate 0.1 h?1, the content of acetic acid is kept in low level and dissolved oxygen response signal is oscillated along with the pulses in feed rate in fed-batch phase. The critical specific oxygen uptake rate is reduced by induction of recombinant human epidermal growth factor. Consequently, acetic acid is readily accumulated in the medium and the dissolved oxygen response signal loses its oscillation characteristics. According to the dissolved oxygen response signal, using feedback control, the feed rate in post-induction phase is effectively manipulated and acetic acid accumulation is avoided successfully. Cell concentration of 48 g?L?1 dry cell weight can be obtained and the level of human epidermal growth factor is increased 45 % comparing with that of fed-batch cultivation without feedback control.更多还原