Lipases are one of the groups of enzymes with the highest number of industrial and biotechnological applications, processing of dairy foods and oils, detergents, cosmetics, leather, pharmaceuticals, paper, production of surfactants, biodiesel and recently as a promising alternative for the treatment of wastewater contaminated with lipids. In this study, microorganisms were isolated from wastewater samples containing fats and extracellular lipase production was determined using p-nitrophenylpalmitate. From the 149 isolates obtained, 37 showed lipolytic activity and strain CCEI-1, identified as Serratia marcescens, had the highest activity at alkaline pH and at 30°C. Also degraded lipids and produced pigmentation on solid medium at pH 8,0 and 50°C. The culture supernatants of S. marcescens used to determine thermal stability at 50°C indicate that the enzyme is stable at this temperature and at alkaline pH. The enzyme was partially purified and electrophoresed (SDS-PAGE) where bands between 40 and 116 kDa were detected. The results obtained in this study indicate that the strain CCEI-1 of S. marcescens can be a possible source of thermostable lipases with industrial and biotechnological applications.