5-酮基-D-葡萄糖酸发酵生产的工艺条件优化

葡萄糖酸氧化杆菌可将葡萄糖转化为5-酮基-D-葡萄糖酸(5-KGA),而5-KGA是重要食品添加剂L(+)-酒石酸的合成前体。为提高5-KGA产量及其对葡萄糖的转化率,对5-KGA发酵生产的工艺条件进行优化。在摇瓶水平最适的培养基和培养条件下,5-KGA最高产量为19.7 g/L,较优化前提高43.8%。在5 L发酵罐上控制恒定pH值5.5、溶氧浓度15%条件下,5-KGA产量达到46.0 g/L,较摇瓶最高产量提高1.3倍,应用葡萄糖流加工艺,5-KGA最高产量达到75.5 g/L,转化率超过70%,与已见报道的最高水平相比提高了32.0%,为实现微生物发酵生产5-KGA、进而合成L(+)-酒石酸的工业化提供了切实有效的途径。

Optimization of the fermentation conditions for 5-keto-D-gluconic acid production

Gluconobacter oxydans converts glucose to gluconic acid and subsequently to 5-keto-D-gluconic acid (5-KGA), a precursor of industrially important L(+)-tartaric acid. To increase the yield of 5-KGA, fermentation conditions of 5-KGA production was optimized. Under the optimum medium and culture conditions in the shake flask, the highest 5-KGA production reached 19.7 g/L, increased by 43.8% after optimization. In a 5-L bioreactor, the pH was controlled at 5.5 and dissolved oxygen (DO) at 15%, 5-KGA production reached 46.0 g/L, raised at least 1.3 times than in the shake flask. Glucose feeding fermentation process was further developed, and the highest 5-KGA production of 75.5 g/L with 70% of yield was obtained, 32.0% higher than the highest reported value. Therefore, this newly developed fermentation process provided a practical and effective alternative for the commercial production of 5-KGA, and further of L(+)-tartaric acid.