Bartek Tobias, Makus Pia, Klein Bianca, Lang Siegmund, Oldiges Marco
Institute of Biotechnology 2, Forschungszentrum Jülich, 52425 Jülich, Germany.
Bioprocess Biosyst Eng. 2008 Apr;31(3):217-25. doi: 10.1007/s00449-008-0202-z. Epub 2008 Jan 26.
The effect of different amounts of supplemented L-isoleucine and pantothenate has been analysed with the auxotrophic strain Corynebacterium glutamicum DeltailvA DeltapanB, showing that the final biomass concentration of this preliminary L-valine production strain can be controlled by the amount of added L-isoleucine. One gramme cell dry weight is formed from 48 micromol L-isoleucine. Different amounts of available pantothenate affect the intracellular pyruvate concentration. By limiting pantothenate supplementation from 0.8 to 0.1 microM, a 35-fold increase of cytoplasmic pyruvate up to 14.2 mM can be observed, resulting in the increased formation of L-valine, L-alanine and organic acids in the presence of low pantothenate concentrations. These findings can be used to redirect the carbon flux from glycolysis via pyruvate to the TCA cycle towards the desired product L-valine.
利用营养缺陷型菌株谷氨酸棒杆菌ΔilvAΔpanB分析了不同添加量的L-异亮氨酸和泛酸盐的作用，结果表明，这种初步的L-缬氨酸生产菌株的最终生物量浓度可通过添加的L-异亮氨酸量来控制。每48微摩尔L-异亮氨酸可形成1克细胞干重。不同量的可用泛酸盐会影响细胞内丙酮酸浓度。通过将泛酸盐添加量从0.8微摩尔限制到0.1微摩尔，可观察到细胞质丙酮酸增加35倍，达到14.2毫摩尔，在低泛酸盐浓度下会导致L-缬氨酸、L-丙氨酸和有机酸的生成增加。这些发现可用于将糖酵解途径中通过丙酮酸到三羧酸循环的碳通量重定向到所需产物L-缬氨酸。
