枯草芽孢杆菌(Bacillus subtilis)发酵生产乙偶姻的pH调控策略

Two-stage pH control strategy of acetoin production by Bacillus subtilis CCTCC M 208157

摘要:

【目的】为了提高Bacillus subtilis CCTCC M 208157发酵生产乙偶姻的效率。【方法】在7 L发酵罐水平上考察不同pH条件对菌株生长及乙偶姻合成的影响。【结果】pH对菌株合成乙偶姻有显著影响, pH 4.5有利于细胞合成乙偶姻, 但是延迟期较长; pH 5.5时菌株生长较快, 但乙偶姻的产量偏低。因此提出了两阶段pH控制策略: 发酵前期(0?16?h), 控制pH 5.5; 发酵中后期(16?72 h), 控制pH 4.5。【结论】通过此策略, 菌株合成乙偶姻的能力得到进一步提高, 乙偶姻的产量、产率和生产强度分别为32.7 g/L、0.41?g/g和0.91 g/(L·h), 分别比初始发酵条件下提高了41%、42%和69%。

Abstract:

[Objective] In order to improve the acetoin production efficiency by Bacillus subtilis CCTCC M 208157. [Methods] The processes of acetoin fermentation were investigated under various pH conditions in a 7 L fermentor. [Results] The effects of pH on cell growth and acetoin production showed that the optimum pH for acetoin production and cell growth were 4.5 and 5.5, respectively. Based on the above results, a two-stage pH control strategy was developed: the pH was controlled at 5.5 for the first 16 h, and then decreased to 4.5 for the remaining time. [Conclusion] With this optimized pH control strategy, the production of acetoin had a significant improvement. Moreover, the production, conversion rate from glucose and productivity of acetoin were achieved at 32.7 g/L, 0.41 g/g and 0.91 g/(L·h), respectively, which were 41%, 42% and 69% higher than that from the strategy without pH control.