Establishment of oxidative D-xylose metabolism in Pseudomonas putida S12.
The oxidative D-xylose catabolic pathway of Caulobacter crescentus, encoded by the xylXABCD operon, was expressed in the gram-negative bacterium Pseudomonas putida S12. This engineered transformant strain was able to grow on D-xylose as a sole carbon source with a biomass yield of 53% (based on g [dry weight] g D-xylose(-1)) and a maximum growth rate of 0.21 h(-1). Remarkably, most of the genes of the xylXABCD operon appeared to be dispensable for growth on D-xylose. Only the xylD gene, encoding D-xylonate dehydratase, proved to be essential for establishing an oxidative D-xylose catabolic pathway in P. putida S12. The growth performance on D-xylose was, however, greatly improved by coexpression of xylXA, encoding 2-keto-3-deoxy-D-xylonate dehydratase and alpha-ketoglutaric semialdehyde dehydrogenase, respectively. The endogenous periplasmic glucose dehydrogenase (Gcd) of P. putida S12 was found to play a key role in efficient oxidative D-xylose utilization. Gcd activity not only contributes to D-xylose oxidation but also prevents the intracellular accumulation of toxic catabolic intermediates which delays or even eliminates growth on D-xylose.
Meijnen
Jean-Paul
JP
Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands. J.P.Meijnen@tudelft.nl
de Winde
Johannes H
JH
Ruijssenaars
Harald J
HJ
D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D016935:Caulobacter crescentus / Q000201:enzymology / Q000235:genetics; D017353:Gene Deletion; D005818:Genetic Engineering; D042843:Glucose 1-Dehydrogenase / Q000235:genetics / Q000378:metabolism; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D009876:Operon; D016958:Pseudomonas putida / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D014994:Xylose / Q000378:metabolism*
D001426:Bacterial Proteins; D014994:Xylose; D042843:Glucose 1-Dehydrogenase; D000445:Aldehyde Oxidoreductases; C020070:2,5-dioxovalerate dehydrogenase; C037004:D-xylo-aldonate dehydratase; D006836:Hydro-Lyases