Studies on bacterial utilization of uronic acids. 4. Alginolytic and mannuronic acid oxidizing isolates.

Several species of bacteria are known to utilize galacturonic and glucuronic acids (Thofern and Hollmann, 1956; Payne and Carlson, 1957; and McRorie, Williams, and Payne, 1959), but there have been no reports of utilization of mannuronic acid. DeLey (1953) and Starr, DeLey, and Kilgore (1957) observed that Aerobacter cloacae and Erwinia carotovora did not metabolize this acid. We have found (Payne and McRorie, 1958) that uronic isomerase from Serratia marcescens produced barely detectable quantities of keturonic acid from mannuronic acid, but whole cells did not oxidize this alduronic acid. It seems likely, therefore, that mannuronate is metabolized differently from the other uronic acids. Bacteria which hydrolyze alginic acid are known (Waksman, Carey, and Allen, 1934). Since mannuronic acid is the major hydrolytic product of this polymer, it seemed probable that these bacteria will utilize this substrate. That has proved to be true with two isolates obtained in our laboratory. This paper describes the isolation and some properties of these two organisms, Alginomonas alginica from brown algae obtained at Sapelo Island, Georgia, and a less actively alginolytic pseudomonad from soil by enrichment culture. These bacteria oxidize mannuronate with constitutive enzymes, whereas galacturonic and glucuronic acids are not metabolized.