Isolation, characterization, and physiology of bacteria able to degrade nitrilotriacetate

Until recently, only three obligately aerobic bacteria (affiliated with the genus Pseudo-monas) that can grow with nitrilotriacetate (NTA) as their only source of carbon, nitrogen, and energy have been isolated and studied in pure culture. By employing a different isolation strategy than was used previously, several nonpseudomonads were isolated in pure culture from both soil and wastewater that are able to utilize NTA under aerobic growth conditions. Additionally, a denitrifying bacterium was isolated from river sediment that is able to utilize NTA in the absence of oxygen. These isolates have been characterized with respect to their cell morphology and physiology. The data collected so far do not allow classification of both the gram-negative and the gram-positive strains isolated, and the taxonomic position of the isolates remains obscure. However, properties like C1 utilization, production of acetoin, and nonmotility clearly indicate that the gram-negative strains do not belong to the genus Pseudomonas. Information is presented on the regulation of NTA-metabolizing enzymes in isolate TE 1 suggesting that these enzymes are inducible in this bacterium.