Archives of Microbiology

, Volume 175, Issue 1, pp 52–61

Different glycolytic pathways for glucose and fructose in the halophilic archaeon Halococcus saccharolyticus

  • Ulrike Johnsen
  • Martina Selig
  • Karina B. Xavier
  • Helena Santos
  • Peter Schönheit
Original Paper

DOI: 10.1007/s002030000237

Cite this article as:
Johnsen, U., Selig, M., Xavier, K. et al. Arch Microbiol (2001) 175: 52. doi:10.1007/s002030000237

Abstract.

The glucose and fructose degradation pathways were analyzed in the halophilic archaeon Halococcus saccharolyticus by 13C-NMR labeling studies in growing cultures, comparative enzyme measurements and cell suspension experiments. H. saccharolyticus grown on complex media containing glucose or fructose specifically 13C-labeled at C1 and C3, formed acetate and small amounts of lactate. The 13C-labeling patterns, analyzed by 1H- and 13C-NMR, indicated that glucose was degraded via an Entner-Doudoroff (ED) type pathway (100%), whereas fructose was degraded almost completely via an Embden-Meyerhof (EM) type pathway (96%) and only to a small extent (4%) via an ED pathway. Glucose-grown and fructose-grown cells contained all the enzyme activities of the modified versions of the ED and EM pathways recently proposed for halophilic archaea. Glucose-grown cells showed increased activities of the ED enzymes gluconate dehydratase and 2-keto-3-deoxy-gluconate kinase, whereas fructose-grown cells contained higher activities of the key enzymes of a modified EM pathway, ketohexokinase and fructose-1-phosphate kinase. During growth of H. saccharolyticus on media containing both glucose and fructose, diauxic growth kinetics were observed. After complete consumption of glucose, fructose was degraded after a lag phase, in which fructose-1-phosphate kinase activity increased. Suspensions of glucose-grown cells consumed initially only glucose rather than fructose, those of fructose-grown cells degraded fructose rather than glucose. Upon longer incubation times, glucose- and fructose-grown cells also metabolized the alternate hexoses. The data indicate that, in the archaeon H. saccharolyticus, the isomeric hexoses glucose and fructose are degraded via inducible, functionally separated glycolytic pathways: glucose via a modified ED pathway, and fructose via a modified EM pathway.

Halococcus saccharolyticus Archaea Modified Embden-Meyerhof pathway Modified Entner-Doudoroff pathway 13C-NMR Ketohexokinase Fructose-1-phosphate kinase Glucose dehydrogenase Gluconate dehydratase 2-Keto-3-deoxy-gluconate kinase

Copyright information

© Springer-Verlag 2000

Authors and Affiliations

  • Ulrike Johnsen
    • 1
  • Martina Selig
    • 1
  • Karina B. Xavier
    • 2
  • Helena Santos
    • 2
  • Peter Schönheit
    • 1
  1. 1.Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1–9, 24118 Kiel, Germany
  2. 2.Instituto de Tecnologia Quimica e Biológica, Apartato 127, 2780 Oeiras, Portugal