LYPOLYTIC ACTIVITY OF ANTARCTIC COLD-ADAPTED MARINE BACTERIA (TERRA NOVA BAY, ROSS SEA)

Aims: The aim of this study was to investigate the lipolytic activity of coldadapted Antarctic marine bacteria and, furthermore, the combined effect of some environmental factors on this enzymatic process. Methods and Results: Strains were assayed for lipolytic activity on a basal medium amended with seven individual fatty acid esters. A significant activity was observed for 148 isolates (95Æ5% of the total screened). The interactive effect of pH, temperature and NaCl concentration on the substrates was tested for six representative isolates, identified as Pseudoalteromonas, Psychrobacter and Vibrio. Differences between strains according to NaCl and pH tolerances were observed. Only one strain degraded the substrate more efficiently at 4C than at 15C. Conclusions: Our findings demonstrate that the lipolytic activity of Antarctic marine bacteria is rather variable, depending on culture conditions, and occurs in a wide range of salt concentration and pH. Significance and Impact of the Study: Isolation and characterization of bacteria that are able to efficiently remove lipids at low temperatures will provide insight into the possibility to use cold-adapted bacteria as a source of exploitable enzymes. Moreover, research on the interactive effects of salt concentration, pH and temperature will be useful to understand the true enzyme potentialities for industrial applications.