The Mechanism of Allantoin Degradation by a Pseudomonas

Animals and plants are known to convert al-lantoin to glyoxylic acid and urea via allantoic acid (Laskowski, 1951). Bacteria and yeasts are known to decompose allantoin, but evidence as to the pathway is very incomplete. Barker (1943) has reported that Streptocus allantoic de-grades allantoin anaerobically, giving rise to ammonia, urea, carbon dioxide, formic, acetic, lactic, and oxamic acids and possibly glycolic acid. It has been postulated from growth studies with bacteria (Young and Hawkins, 1944) and yeast (DiCarlo et al., 1953) that the aerobic decomposition of allantoin occurs via allantoic acid yielding glyoxylic acid and urea. The present paper reports on the mechanism of allantoin degradation by an unidentified species of Psudomonas isolated by enrichment culture techniques. Cell-free extracts of this organism decompose allantoin yielding urea, carbon dioxide, and water. The intermediates along the degradative pathway have been isolated and identified as allantoic, glyoxylic, and formic acids EXPERIMENTAL METHODS AND RESULTS Isolation of the organism. An enrichment me-dium containing allantoin, 0.3 per cent; yeast extract (Difco), 0.1 per cent; and KsHPO4, 0.1 per cent in distilled water, pH 7.2, was inoculated with San Francisco bay mud. Abun-dant growth was obtained in 24 hours at 30 C in an aerobic culture incubated on a shaker. Successive transfers were made in the same medium at daily intervals for one week and finally plated out on the. same medium supple-mented with 1.5 per cent agar. The predominant strain was isolated and designated as 2RCC-1.