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• Bioengineering •     Next Articles

Effect of unsaturated glucose addition on L-isoleucine production by Corynebacterium glutamicum

1,Liu JingYang2,XU Qingyang   

  • Received:2020-07-07 Revised:2021-06-05 Online:2021-10-25 Published:2021-10-27
  • Contact: XU Qingyang E-mail:xuqingyang@tust.edu.cn

Abstract: The low yield and high concentration of by-products represents a primary limiting factor in biosynthesis of L-isoleucine using Corynebacterium glutamicum, which significantly hinders the industrial production of L-isoleucine. In this work, we demonstrated a better glucose feeding rate depending on different growth period of Corynebacterium glutamicum. which is as following: ( 0-8 h(0 g/(L·h))、8-14 h(5.40-7.47 g/(L·h))、16-24 h(7.47-7.00 g/(L·h))、24-40 h(7.00-5.20 g/(L·h). The fermentation results showed that this optimized sugar supplement rate enabled the Corynebacterium glutamicum YILM1504 to produce 44.32 g/L L-isoleucine with a yield of 19.63% under the restricted sugar supplement fermentation process. The comparative analysis of metabolic flow revealed that a better ratio of carbon distribution between EMP and HMP was obtained (0.56). Moreover, the metabolic flow into Ile was increased by 18.92%, and the metabolic flow into Val, Leu, and Ala was reduced by 67.12%, 72.21%, and 30.23%. In conclusion, this method provides a precisely optimized glucose feeding strategy to maintain dynamic glucose demand of Corynebacterium glutamicum during different fermentation period, which resulted in enhanced isoleucine titer, reduced by-products accumulation and significantly prolonged acid production peak period.

Key words: L-isoleucine, Glucose amount of unsaturated glucose added, Clostridium glutamate, Metabolic flow

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