STUDIES ON OXIDATIVE FERMENTATION

I. ON THE FORMATION OF NEW SUBSTANCES OF POSITIVE FERRIC CHLORIDE REACTION BY GLUCONOACETOBACTER LIQUEFACIENS FROM GLUCOSE

Abstract

(1) The authors studied the oxidation of D-glucose, D-fructose, D-mannose, D-galactose, D-xylose, and L-arabinose by surface and shaking cultures of Gluconoacetobacter liquefaciens.
(2) The production of organic acids from these sugars was studied by paper chromatographic techniques and 8 spots from D-glucose, one spot from D-fructose, D-mannose, D-galactose, 3 spots from D-xylose, 2 spots from L-arabinose were detected on the paper chromatograms. The production of D-mannonic acid from D-mannose, D-galactonic acid from D-galactose, D-xylonic acid from D-xylose, and L-arabonic acid from L-arabinose were assumed.
(3) The oxidation of glucose was studied in detail. When CaCO₃ was not added to the shaking culture, glucose was oxidized very slowly. When CaCO₃ was added to the shaking culture, glucose was oxidized rapidly and the organic acid with the R_F value of 0.02 was produced at first and then the production of organic acids with the R_F, values of 0.22-0.25, 0.33-0.35, 0.43-0.47, 0.60-0.65, and 0.90 followed. Three spots with the R_F values of 0.02, 0.47-0.50, and 0.60-0.65 were detected with ferric chloride solution.
(4) Isolation and identification of oxidative products from glucose were tried. Aldehyde, formic-, acetic-, 5-keto-D-gluconic-, glycolic-, and tartronic acid, other unknown reducing acids and three substances which gave reddish violet color reactions were isolated from the culture liquid by shaking culture.
(5) Three substances of positive ferric chloride reaction were isolated as crystals, showing the melting point of 203.5°, 230° and 275°, respectively. All of them were recognized as γ-pyrone compounds and the former two were recognized as new substances. Since these γ-pyrone compounds were found to be produced by other oxidative bacteria, for example by Acetobacter 1955 Studies on Oxidative Fermentation. I. 29 melanogenum, which produced reddish brown pigment in the fermentation liquor, these new substances were named "Rubiginol" and "Rubiginic acid" ("rubiginosus" means" reddish brown").
(6) These three γ-pyrone compounds were found to be produced from D-glucose by Gluconoacetobacter liquefaciens when it was incubated by shaking culture with the addition of CaCO₃, but not without CaCO₃. They were not produced from glucose by surface culture both with and without CaCO₃.
From D-fructose, D-mannose, D-galactose, D-xylose, and L-arabinose, we could not find the formation of the substances of positive ferric chloride reaction both in shaking and in surface culture.