Influence of temperature and culture media on growth and lipolytic activity of deep-sea Halomonas sulfidaeris LAMA 838 and Marinobacter excellens LAMA 842

Abstract

Bacteria with lipolytic activity are widespread in the marine environment. These organisms can be used as a source of lipases with activity in unusual conditions such as low temperatures and high salinities. These characteristics allow them to be applied to several industrial processes and products including wastewater treatment and detergent production. In this context the lipolytic activity of bacteria isolated from deep-sea sediments of the South Atlantic was evaluated. Among the collection studied, two strains, Halomonas sulfidaeris LAMA 838 and Marinobacter excellens LAMA 842, were selected for further analysis concerning their growth and lipolytic activity in different temperatures and culture media. Both strains were characterized as mesophiles: H. sulfidaeris LAMA 838 grew best at 30ºC, while M. excellens LAMA 842 showed a maximum growth rate between 20 and 25ºC. Maximum lipolytic activity for both microorganisms was observed above 45ºC, but only M. excellens LAMA 842 had lipolytic activity at low temperatures (5ºC) as well. Considering the culture media employed, H. sulfidaeris LAMA 838 grew better in marine broth without Tween 40, while M. excellens LAMA 842 grew best in marine broth supplemented with Tween 40. Both organisms had maximum lipolytic activity in rich or minimal media supplemented with Tween 40. These results demonstrate the potential of deep-sea bacteria as sources of lipases and indicate conditions that may be used in their cultivation and for the production of industrially relevant enzymes.

Keywords

• Deep-sea bacteria
• microbial growth
• lipolytic activity
• Psychrotolerants