Enhanced 1,3‐propanediol production in Klebsiella pneumoniae by a combined strategy of strengthening the TCA cycle and weakening the glucose effect

Aims This study aimed to strengthen the reducing equivalent generation in Klebsiella pneumoniae for improving 1,3‐propanediol (PDO) production. Methods and Results Disruption of the arcA gene activated the transcription levels of the TCA cycle genes and thus increased the NADH/NAD+ ratio by 54·2%, l...

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Veröffentlicht in:Journal of applied microbiology 2018-03, Vol.124 (3), p.682-690
Hauptverfasser: Lu, X.Y., Ren, S.L., Lu, J.Z., Zong, H., Song, J., Zhuge, B.
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Sprache:eng
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Zusammenfassung:Aims This study aimed to strengthen the reducing equivalent generation in Klebsiella pneumoniae for improving 1,3‐propanediol (PDO) production. Methods and Results Disruption of the arcA gene activated the transcription levels of the TCA cycle genes and thus increased the NADH/NAD+ ratio by 54·2%, leading to the improved PDO titre and yield per cell from 16·1 g l−1 and 4·0 g gDCW−1 to 18·8 g l−1 and 6·4 g gDCW−1 respectively. Further ldhA gene deletion eliminated lactate accumulation and promoted the PDO titre to 19·9 g l−1. Finally, the glucose effect was weakened by deleting the crr gene to enhance the co‐utilization of glucose and glycerol, resulting in the increased PDO production to 23·8 g l−1 with the glycerol conversion rate of 59·5%. The PDO titre in bioreactor was promoted from 61·2 to 78·1 g l−1. Conclusions Deletions of the arcA and the crr genes showed positive effects on the TCA cycle activity and the co‐utilization of glucose and glycerol, leading to the strengthened reducing equivalent generation and the improved PDO titre by 47·8% in shaker. The PDO titre in the bioreactor was enhanced to 78·1 g l−1. Significance and Impact of the Study This study provided novel information on generating reducing equivalent for the PDO biosynthesis by strengthening the TCA cycle and weakening the glucose effect in K. pneumoniae.
ISSN:1364-5072
1365-2672
DOI:10.1111/jam.13685