OXIDATION OF MONO- AND DISACCHARIDES TO ALDONIC ACIDS BY PSEUDOMONAS SPECIES

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Abstract
A number of pentoses, hexoses and disaccharides are oxidized to the corresponding aldonic acid when Pseudomonas quercito-pyrogallica, P. calcoacetica and P. aromatica are grown on a peptone medium containing the carbohydrate. The oxidation of the disaccharides, maltose, lactose, cellobiose and melibiose, and in addition, glucose, was studied in detail using a particulate preparation obtained from P. quercito-pyrogallica by sonic treatment. One atom of O2 was consumed per mole of sugar oxidized without formation of H202 A possible role for cytochrome carriers was indicated. The system was not stimulated by the addition of di- or triphosphopyridine nucleo-tide, flavin adenine dinucleotide or flavin monophosphate. Treatment with Versene followed by dialysis resutled in inactivation; activity was restored by several cations (divalent Fe, Mg, Mn Co) to varying degrees, and to 100% of the original activity with Ca. The system was slightly more active with B than with a-D-glucose and also contained an active lactonase. The formation of the aldonic acid is probably by way of the lactone. The cleavage of the glycosidic bond in the disaccharides was not observed in short term growth studies, or in manometric experiments with washed cells or particulate preparations. The dissacharides do not contribute C for cell growth.