This study focused on use of bacterial extracellular enzyme activities as biochemical parameters,
along with the microbiological and physicochemical characteristics, in a comprehensive assessment of water quality of four lake ecosystems in the Province of Vojvodina (northern Serbia): Provala, Ludas, Zobnatica and Palic. Water samples were collected in June and October, 2008. For assessment of microbiological water quality, heterotrophic plate count, total and fecal coliform count, as well as total bacterial count was determined. Based on microbiological parameters, the water ecosystems were appropriately classified. The following extracellular enzyme activities were determined: alkaline phosphatase, β-D-glucosidase and acetate esterase using fluorogenic 4-methylumbelliferone labeled substrates. The results showed that Provala Lake had the best
water quality taking in consideration all of the parameters, followed by Zobnatica, while Ludas and Palic had a significant level of organic water pollution both in June and October. The results indicate that further similar studies should include both microbiological and biochemical analyses, in order to obtain more relevant data on
water quality.