ABSTRACT
The bulk of organic substances in aquatic environments are macromolecular and not ready for incorporation into the bacterial cell. These materials have to be preconditioned by extracellular enzymes, so that they can be available for bacterial growth and nutrient cycles. The activity of these enzymes is a limiting factor for substrate decomposition and bacterial growth. The quantitative estimates of total bacterial extracellular enzyme activity are completed by rapid and sensitive tests for the detection of enzymatic properties of bacterial isolates. The methods used for these purposes are based on the application of fluorogenic model substrates. The method of determining bacterial extracellular enzyme activity (EEA) is valid for all types of natural waters and also, for waste water and drinking water. Using special application techniques, it applies to undisturbed sediment cores. The measurement of EEA is independent of water volume, because the fluorescent end-product of hydrolysis is not bound to particles or incorporated by them, but exists dissolved in the water.
