Glyoxylate Oxidation In Acetobacter With Reference To The Formation Of Oxalic Acid

Abstract

Oxalic acid production from glucose by Acetobacter was first discovered in 1900 by ZOPE (1) in three species of Acetobacter: Bacterium aceti, Bact. pasteurianum and Bact. Kutzingianum. Later, Bad. xylinum, Bad. acetigenum, Bad. ascendens and Bad. acetosum were added to the above species by the same author. In 1902 BANNING (2) reported that Thermobacterium aceti, Bad. oxy-dans, Bad. industrium and Bad. acidi oxalici formed oxalate not only from sugars but also from alcohols and organic acids. Further, HENNEBERG (3) reported in 1906 Bad. curvum and Bad. Schützenbachi as oxalic acid formers. As is evident from these early reports, many species of acetic acid bacteria can form oxalic acid from various substrates. The mechanism of the oxalate formation has been mainly studied with fungi on account of their ability to accumulate a high concentration of oxalic acid from sugars. Recently, HAYAISHI and his associates (4) found that oxalacetate is hydrolyzed to give acetate and oxalate by cell free extracts of Aspergillus niger. On the other hand, CHALLENGER, SUBRAMANIUM and WALKER (5) in 1927 proposed the direct oxidation mechanism of acetate to oxalate and reported the formation of calcium oxalate from calcium acetate in the culture of Asp. niger. They identified glycolic acid as one of its intermediates and reported on their success in isolating ammonium oxalate formed from ammonium glycolate. Although they did not prove the direct formation of oxalate from glyoxylate, they isolated glyoxylate as an amino guanidine derivative from the calcium acetate medium of Asp. niger. The following hypothetical scheme was proposed, based on these experiments. However, direct evidence for the formation of oxalic acid from glyoxylic acid has not been obtained. TANAKA and his coworkers (6) in 1942 observed that glycolate was the best substrate for the oxalate formation and emphasized the possibility of the oxalate formation via glycolic acid as a side reaction in the active acetate combustion. Recently, ASAI, KIDA and KASAI (unpublished) demonstrated the existence of TCA cycle and glyoxylate by-path as the terminal oxidation system in Acetobacter dioxyacetonicus strain A 15. Using intact cells of this organism, they also confirmed the occurrence of oxidation of glyoxylate to oxalate. A TPN1 and CoA requiring enzyme which catalyses a similar oxidation reaction was recently found by QUAYLE and TAYLOR (7) in Pseudomonas oxalaticus grown in an oxalate-containing medium. This report deals with the enzyme system involved in the glyoxylate oxidation in Acetobacter dioxyacetonicus. From the particulate fraction of cell free extracts of this bacterium, separation was made of an oxidase system which oxidizes specifically the aldehyde group of glyoxylate to produce oxalate. Several properties of this enzyme system will be discussed. © 1963, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation. All rights reserved.