Effect of dissolved oxygen concentration on the metabolism of glucose inPseudomonas putida BM014

The effect of dissolved oxygen concentration on the metabolism of glucose inPseudomonas putida BM014 was investigated. Glucose was completely converted to 2-ketogluconatevia extracellular oxdative pathway and then taken up for cell growth under the condition of sufficient dissolved oxygen concentration. On the other hand, oxygen limitation below dissolved oxygen tension (DOT) value of 20% of air saturation caused the shift of glucose metabolism from the extracellular oxidative pathway to the intracellular phosphorylative pathway. Specific activities of hexokinase and gluconate kinase in intracellular phosphorylation pathway decreased as the DOT increased, while 2-ketogluconokinase activity in extracellular oxidative pathway increased under the same condition. This result can be usefully applied to microbial transformation of glucose to 2-ketogluconate, the synthetic precursor for iso-vitamine C, with almost 100% yieldvia extracellular oxidation by simple DOT control.