Screening of soil samples for isolation of lipase producing organisms

Lipases, falling under serine ester hydrolases can catalyse both the hydrolysis of lipid and long chain triglycerol synthesis. Lipases find wide usage in industry especially in food industry, detergents, leather industry, environmental management, pharmaceutical industry and as biosensor. Bacteria are the most common source of lipases. Soil samples from around petroleum waste, dairy farm and paddy field from in and around Manipal were collected. The soil samples were studied for physical characteristics. Tributyrin agar media was used for screening lipolytic bacteria. One gram of soil sample from various sources was dissolved in 50mL of sterile water separately. The stock solutions were used for log dilution from 10-1 to 10-4. Last two dilutions of each sample were mixed with tributyrin agar media and plated in petri dishes to facilitate growth of lipolytic bacteria. Morphological characteristics of grown colonies were recorded and they were isolated and preserved on tributyrin agar slants. Morphology of iso ated organisms was studied. Lipolytic activity was tested in cell free filtrate of broth culture for each isolate using cupric acetate/pyridine reagent at 715 nm. Enzyme activity was measured using standard curve prepared with stearic acid. A total of 12 different colonies (4 from each sample) were isolated and studied. Among the different isolates, many were found to be spherical, non-motile and Gram positive. One isolate from dairy farm showed promising lipolytic activity. Further studies on identification of the organism and optimization parameters are to be carried out.