Role of the pentose phosphate pathway and the Entner–Doudoroff pathway in glucose metabolism of Gluconobacter oxydans 621H
- 752 Downloads
Glucose catabolism by the obligatory aerobic acetic acid bacterium Gluconobacter oxydans 621H proceeds in two phases comprising rapid periplasmic oxidation of glucose to gluconate (phase I) and oxidation of gluconate to 2-ketogluconate or 5-ketogluconate (phase II). Only a small amount of glucose and part of the gluconate is taken up into the cells. To determine the roles of the pentose phosphate pathway (PPP) and the Entner–Doudoroff pathway (EDP) for intracellular glucose and gluconate catabolism, mutants defective in either the PPP (Δgnd, Δgnd zwf*) or the EDP (Δedd–eda) were characterized under defined conditions of pH 6 and 15 % dissolved oxygen. In the presence of yeast extract, neither of the two pathways was essential for growth with glucose. However, the PPP mutants showed a reduced growth rate in phase I and completely lacked growth in phase II. In contrast, the EDP mutant showed the same growth behavior as the reference strain. These results demonstrate that the PPP is of major importance for cytoplasmic glucose and gluconate catabolism, whereas the EDP is dispensable. Reasons for this difference are discussed.
KeywordsGluconobacter oxydans gnd zwf edd eda Glucose
We are most grateful to Armin Ehrenreich and Wolfgang Liebl (TU München) for providing the strain and protocol used for generating the G. oxydans deletion mutants. We also thank DSM Nutritional Products (Kaiseraugst, Switzerland) for the financial support and Dietmar Laudert, Günter Pappenberger, and Hans-Peter Hohmann (DSM Nutritional Products) for their scientific input and their continued disposition for discussion. This work was funded by the German Ministry of Education and Research (BMBF) within the GenoMik-Transfer program (grant 0315632D).
- Kersters K, Lisdiyanti P, Komagata K, Swings J (2006) The family Acetobacteriaceae: the genera Acetobacter, Acidomonas, Asaia, Gluconacetobacter, Gluconobacter and Kozakia. In: Dworkin M, Falkow S, Rosenberg E, Schleifer K-H, Stackebrandt E (eds) The prokaryotes, vol. 5, 3rd edn. Springer, Heidelberg, pp 163–200Google Scholar
- Matsushita K, Fujii Y, Ano Y, Toyama H, Shinjoh M, Tomiyama N, Miyazaki T, Sugisawa T, Hoshino T, Adachi O (2003) 5-keto-d-gluconate production is catalyzed by a quinoprotein glycerol dehydrogenase, major polyol dehydrogenase, in Gluconobacter species. Appl Environ Microbiol 69:1959–1966CrossRefGoogle Scholar
- Miyazaki T, Tomiyama N, Shinjoh M, Hoshino T (2002) Molecular cloning and functional expression of d-sorbitol dehydrogenase from Gluconobacter suboxydans IF03255, which requires pyrroloquinoline quinone and hydrophobic protein SldB for activity development in E. coli. Biosci Biotechnol Biochem 66:262–270CrossRefGoogle Scholar
- Peters B, Junker A, Brauer K, Mühlthaler B, Kostner D, Mientus M, Liebl W, Ehrenreich A (2012) Deletion of pyruvate decarboxylase by a new method for efficient markerless gene deletions in Gluconobacter oxydans. Appl Microbiol Biotechnol. doi:10.1007/s00253-00012-04354-zGoogle Scholar