Characterization of a bacterium (A-1) that decomposes ferric chelate of EDTA in photographic processing waste solutions

A Ferric-EDTA(Fe-EDTA)-degrading bacterium, strain A-1 was characterized by it:; physiological properties. The rate of degradation of Fe-EDTA was meas ured by the titration method and ion chromatography. The former method has the advantage of allowing a greater number of sample measurements of sample s at one time. The rate of degradation of Fe-EDTA was higher in a stationar y culture than in a shaked one. The optimum pH for the degradation rate was approximately 8.2. Strain A.-l grew in the presence of various kinds of me tal-EDTA chelates, but a Na salt, Mg and Ca chelates of EDTA inhibited the growth. Their MICs (minimual inhibitory concentration) were 0.0045, 0.03 an d 0.006 %, respectively. These characteristics of strain A-1 have similarit ies to those of strain B-3, but were different from those of Agrobacterium sp. which were reported by Lauff previously (Appl. Environ. Microbiol., 56, 3346 (1990)). All of the detail taxonomic characters indicate that the iso late strain A-1 belongs to a Pseudomonas sp.