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Fermentation 2018, 4(2), 44; https://doi.org/10.3390/fermentation4020044

Characterization of the Weimberg Pathway in Caulobacter crescentus

1
Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
2
Applied Microbiology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
Current address: Division of Biotechnology, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
*
Author to whom correspondence should be addressed.
Received: 7 May 2018 / Revised: 7 June 2018 / Accepted: 9 June 2018 / Published: 12 June 2018
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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. View Full-Text
Keywords: Caulobacter crescentus; Weimberg pathway; xylose; arabinose; physiological characterization; enzyme activity Caulobacter crescentus; Weimberg pathway; xylose; arabinose; physiological characterization; enzyme activity
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Almqvist, H.; Jonsdottir Glaser, S.; Tufvegren, C.; Wasserstrom, L.; Lidén, G. Characterization of the Weimberg Pathway in Caulobacter crescentus. Fermentation 2018, 4, 44.

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