[Conditions of exolipase biosynthesis by the fungus Oospora fragrans]

The fungal strain Oospora fragrans isolated from sunflower seeds had a high lipase activity, especially on the media containing soybean flour and various oils. The fungal lipase showed inductive characteristics, the best inducers being olive and soybean oils. The biosynthesis of lipase from O. fragrans occurred at the optimal temperature of 26-30 degrees C and strong aeration. Maximun of lipolytic activity did not coincide with maximum accumulation of biomass and developed at the log-phase of the fungal growth. With age the lipid content in the mycelium increased in parallel with the biomass accumulation. Mycelial lipids of O. fragrans contained nine fractions, among which fatty acids and triglycerides were in predominance. The study of properties of O. fragrans lipase showed a high pH value and thermal stability, the capacity to function at low temperatures, and activity towards many substrates. The enzyme readily hydrolyzed not only natural vegetable (olive, linseed and mustard) oils but also oils of microorganisms grown on petroleum hydrocarbons.