Characterization of the Weimberg Pathway in Caulobacter crescentus

Henrik Almqvist, Sara Jonsdottir Glaser, Celina Tufvegren, Lisa Wasserstrom, Gunnar Lidén

Research output: Contribution to journalArticlepeer-review

1 Citation (SciVal)

Abstract

Caulobacter crescentus is a gram-negative bacterium that can utilize xylose as a substrate using the Weimberg pathway, which converts xylose to α-ketoglutarate in five steps without carbon loss. This is an interesting pathway for heterologous expression in other organisms in order to enable xylose utilization in biorefinery processes. C. crescentus was grown on xylose, arabinose and glucose, and maximum specific growth rates determined for the three substrates were 0.11 h−1, 0.05 h−1, and 0.15 h−1 respectively. Growth was found to be significantly inhibited at sugar concentration of 20 g L−1, shown primarily by an increased lag phase. Enzyme activity assays showed that the Weimberg pathway was active in cells grown, not only on xylose but also on arabinose. No activity was found for growth on glucose. Furthermore, substantial amounts of α-ketoglutarate—up to a yield of 0.4 g g−1—was excreted during growth on xylose, but no other extracellular intermediates in the Weimberg pathway were detected during growth on xylose. Apparently, C. crescentus is not well adapted for efficient growth on high xylose levels, and responds by an extended lag phase and secretion of α-ketoglutarate.
Original languageEnglish
Article number44
Number of pages11
JournalFermentation MDPI
Volume4
Issue number2
DOIs
Publication statusPublished - 2018 Jun 12

Subject classification (UKÄ)

  • Microbiology

Keywords

  • Caulobacter crescentus
  • Weimberg pathway
  • xylose
  • arabinose
  • physiological characterization
  • enzyme activity

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