SEROLOGICAL STUDIES ON NITRILOTRIACETIC ACID (NTA)-UTILIZING BACTERIA- DISTRIBUTION OF CHELATOBACTER-HEINTZII AND CHELATOCOCCUS-ASACCHAROVORANS IN SEWAGE-TREATMENT PLANTS AND AQUATIC ECOSYSTEMS

The rather high specificity of polyclonal antibodies raised against th e Gram-negative aerobic NTA-utilizing species Chelatobacter heintzii a nd Chelatococcus asaccharovorans allowed us to study their distributio n by an indirect immunofluorescence test (IFT). In surface waters the fraction of IFT-positive-cells did not exceed 0.1% of the total bacter ial population as determined by acridine orange direct counting (AODC) . In activated sludge the fraction of IFT-positive cells was in the ra nge of 0.1 to 1% suggesting an approximately tenfold enrichment of the NTA-utilizing bacteria in sewage treatment plants. The problems assoc iated with the methodology are discussed and the environmental signifi cance of our results is compared with that of other ecological studies on NTA-utilizing bacteria.