Lipolytic activity was assayed in samples of Antarctic krill frozen in different conditions and in its liquid digesta with synthetic (tributylglycerol, esters of 2-naphtol and fatty acids C3, C9 , C14 and C18 ) and natural (olive oil) substrates. It was testified that the lipolytic activity is several-fold higher in the crustaceans with high food intake than in those with an empty digestive tract. Krill lipases show higher activity against esters of unsaturated fatty acids that against analogous derivatives of saturated ones and 10-fold higher affinity tributylglycerol (Km = 1.12 mM). Their maximal activity is at pH 6.4 and 37°C. E. superba lipases preserve total activity up to 35°C for 45 minutes, and are completely inactivated at 55°C for 5 minutes. Prevailing part of lipolytic activity is present in krill cephalothorax, however, extracts from krill abdomen also display a marked activity. Krill lipases are probably resistant to an attack of crustacean's proteinases.
Sewage and solid waste can be a valuable source of materials used directly or indirectly in manufacturing of usable products. These processes are associated with elimination of pollutants from liquid and solid wastes. The best-known methods of waste management are production of biogas and composting. This paper focuses on the possibility of obtaining biomass as a source of protein feed (whose value, in terms of the composition of aminoacids and microelements, is comparable with conventional feed, e.g. soymeal, bonemeal or fishmeal). Sewage components for bacterial, fungal, algal and vascular plants’ culture are characterized as a source of protein feed. Methods of industrial scale production of enzymes, mainly proteases and lipases that have broad applications in various industries, are discussed. Development perspectives of inexpensive methods of usable products from waste production are showed. Interdisciplinary nature of presented issues, which requires cooperation of specialists in biology, chemistry and technology, is emphasized.