2-Ketogluconic acid oxidation

Oxidation of ETOH Overoxidation of acetic acid Oxidation of lactate Oxidation of glyceror (ketogenesis) Water-soluble brown pigments on GYC 5-ketogluconic acid ... 

Speciation of A. aceti and A. pasteurianus requires the ability to detect oxidation of glycerol to dihydroxyacetone, a property called ketogenesis (see Procedure 2.3.4), as well as the formation of 5-ketogluconic acid from D-glucose. Table 2-4 summarizes expected results for the three important species. 

A 3-deoxy-2-ketogluconic acid 6-phosphate was isolated as an intermediate in the enzymic oxidation of gluconic acid 6-phosphate 135a). The formation of this acid by a dehydration mechanism is reminiscent of that of the saccharinic acids. 

More drastic oxidation of aldoses with hypoiodite leads to keto acids and finally to cleavage of carbon-carbon bonds. Honig and Tempus 199) claimed to have oxidized glucose stepwise to gluconic acid, 2-ketogluconic acid, and n-arabonic acid. However, other workers claim that the main product is 5-ketogluconic acid 200),... 

Acetobacter suboxydans may oxidize glucose to 5-ketogluconic acid (283). Gluconic acid is formed initially and only subsequently is converted to the... 

Shiraishi F, Kawakami K, Kono S, Tamura A (1989a) Continuous production of free gluconic acid by Gluconobacter suboxydans IFO 3290 immobilized by adsorption on ceramic honeycomb monolith effect of reactor configuration on further oxidation of gluconic acid to ketogluconic acid. Appl Microbiol Biotechnol 31 445-447... 

Ketoses are less easily oxidized by acetic acid bacteria. The oxidation of fructose can lead to the formation of gluconic acid and keto-5 fructose. The carbon chain of the sugar can also be divided, resulting in the accumulation of glyceric, glycolic and succinic acid. Especially for the Acetobacter, the final oxidation products of hexose are gluconate and ketogluconate. 

Acetobacter and Pseudomonas strains readily convert glucose to gluconate, and this substance is then oxidized to 2-ketogluconate or to 5-ketogluconate. These substances may be distinguished by the ability of 2-keto acids to form spectrophotometrically detectable quinoxalines. 5-Ketogluconate reduces Benedicts reagent at 25 C. The marked reactivity of the latter presumably... 

According to Koepsell, ferric iron is important in the further oxidation of 2-ketogluconate. This worker has found that the degradation of the keto acid proceeds to a-ketoglutarate and to pyruvate. 

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