ENZYME-IMMUNOASSAY DETECTION OF NITROSOMONAS-EUROPAEA

An exploratory effort to selectively detect the presence of a nitrifyi ng bacterium, Nitrosomonas europaea, successfully demonstrated the fun damental utility of an enzyme-based immunoassay protocol. The applied polyclonal antibody test seemingly offered a marked improvement over t he available analytical options, including plating, activity, and fluo rescence immunoassay techniques. Following an initial purification ste p to enhance overall specificity, this procedure had an apparent lower limit of detection of similar to 5 x 10(6) cells per ml. Tests conduc ted with activated sludge samples exhibited a distinct difference betw een nitrifying and nonnitrifying mixed liquors, although the highest N itrosomonas levels observed (i.e., at 1 to 2% of the overall viable ce ll density) were relatively close to the latter detection boundary.