Lipase biosynthesis by Aspergillus carbonarius in a nutrient medium containing products and byproducts from the oleochemical industry

The process of lipase biosynthesis by Aspergillus carbonarius in a submerged cultivation was studied. It was established that inclusion of a lipid carbon source in the nutrient medium significantly increased enzyme production. Highest lipase activity was achieved when unrefined rapeseed oil (195.61 U/L), soybean oil (155.00 U/L), and soap stock from sunflower oil (149.00 U/L) were used as a carbon source. These three raw materials were characterized by a high acid value, indicating high content of free fatty acids. It was found that the high concentration of free fatty acids in the nutrient medium determined achievement of high lipase activity. Significant increase in lipase biosynthesis was observed when surfactants were included in the nutrient medium. In the presence of 20 g/L Tween 80 lipase activity was more than 2-fold higher in comparison to a control sample. Lipase production was considerably influenced by the presence of organic nitrogen source in the medium. Meat extract was found to stimulate enzyme biosynthesis.