振荡和静态组合式培养改善伊枯草菌素A表达水平

Improvement of iturin A production with a combined shaking and static culture mode by Bacillus subtilis

目的以廉价菜粕作为氮源,对其直接生物利用过程中的碳源种类和培养模式进行优化和改进。方法研究液态静置培养模式下细胞生长和伊枯草菌素生产变化特性,在此基础上提出一种两阶段(振荡+静态)组合式培养模式。结果麸皮作为碳源最有利于伊枯草菌素表达,最高浓度是葡萄糖作为碳源时最高产量的1.6倍;液态静置培养基表面能够形成厚而稳定的生物膜,发酵中后期具有比振荡培养更高的伊枯草菌素生产强度;采用液态振荡和静置组合培养方式伊枯草菌素最高浓度可达1.10 g/L,接近完全振荡培养时的最高水平(1.16g/L)。结论相对于传统的全程式振荡培养而言,这种新的组合培养方式不仅有利于伊枯草菌素高产期(发酵中后期)的过程控制,还能降低整个发酵过程的动力成本。

Objective To optimize and improve the type of carbon source and culture model in the process of bio-utilization when using rapeseed meal as a nitrogen source.MethodsA combined culture mode of first shaking culture following by static biofilm fermentation was proposed based on the changing characteristics ofBacillus subtilis growth and iturin A production under static culture.Results It was indicated that wheat bran was the best carbon source for iturin A production, and the maximum iturin A concentration was 1.6 times higher than that with glucose as a carbon source. Thick and stable biofilm was observed when adopting static culture, and the iturin A productivity was higher than that with traditional shaking culture during the later period of fermentation. Compared to single static culture, the proposed combined culture mode could further improve iturin A production, and the maximum iturin A concentration reached 1.10 g/L, which was close to the highest level produced with single shaking culture (1.16 g/L).Conclusion This new culture strategy can not only decrease the power cost but also can benefit to process control of iturin A in the later period of fermentation.