Research was carried out on the influence of heavy metals on the activity of chitinases produced by chitinolytic bacteria isolated from Moty Bay in Lake Jeziorak. In tests on the concentration of heavy metal ions in the surface water, the highest concentration of copper and zinc ions was found in July in the littoral zone, of cobalt ions in September in the pelagic zone and of lead ions in August, also in the pelagic zone. Studies on the number of chitinolytic bacteria have shown that the highest number of chitinolytic bacteria among the total number of heterotrophic bacteria occurred on macrophytes and in bottom sediments.
The highest percentage of chitinolytic bacteria was found in the surface water, and the lowest in the bottom sediments. As follows from research on the influence of heavy metals on the activity of chitinases, in the majority of the strains tested, heavy metal ions inhibited chitinolytic activity as concentration increased.