Original paper
Bacterial lipolytic activity in an eutrophic lake
Gajewski, Adam J.; Siuda, Waldemar
Archiv für Hydrobiologie Volume 128 Number 1 (1993), p. 107 - 126
63 references
published: Aug 31, 1993
published online: Jun 2, 2021
DOI: 10.1127/archiv-hydrobiol/128/1993/107
ArtNo. ESP141012801007, Price: 29.00 €
Abstract
The kinetics of lipase and distribution of enzyme activity was examined in pelagial and littoral zone and the water column of an eutrophic lake. Bacteria were major producers of lipase activity in lake water. About 15 % of the total activity of lipase in lake water was found in cell-free, 0.2-µm filtrate. The Vmax of lipase activity varied markedly in both sampling sites throughout the study period. Highest Vmax were measured in pelagial (754 nmol L-1 h-1) and in littoral (429 nmol L-1 h-1) samples during spring phytoplankton development in April. Very low Vmax (53 nmol L-1 h-1) was found in littoral in May. The Michaelis constants (Km) of substrate hydrolysis by lipase in lake water ranged between 12-51 µmol/L (littoral) and from 21 to 78 µmol/L (pelagial). High Km values were determined in May, during clear water phase in pelagial (78 µmol/L), and in July (57 and 51 µmol/L in pelagial and littoral, respectively) during summer stratification of the lake. The highest lipase activity was found in samples incubated at pH 7.5, i.e., close to natural pH (7.8) of lake water. Lipase activities of samples decreased when incubated at pH lower and/or higher than 7.5. Various organic compounds, which are bacterial substrates naturally present in lake water, influenced kinetic parameters (Km and Vmax) of lipase in lake water. Palmitic acid induced synthesis of the enzyme in bacteria.
Keywords
eutrophic lake • lipase • phytoplankton