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.
Twelve mineral elements and total ash were examined in regard to the possible use as the estimators of digestibility of natural food in Antarctic seals. Four of them: phosphorus, calcium, copper and zinc have proved to give most reliable results. The estimated total dry mass and organic matter digestibilities of fish food in Weddell seals (Leptonychotes weddelli (Lesson)) averaged 82 and 91%, while the corresponding values for krill eaten by crabeaters (Lobodon carcinophagus (Hombron and Jaequinot)) and leopard seals (Hydrourga leptonyx (Blainville)) reached approximately 87 and 91%, respectively.
The geochemistry of sedimentary rocks is increasingly being used in palaeoenvironmental studies, in the identification of marine versus continental stratigraphy and in chemostratigraphic correlation. The selection of an appropriate research methodology, particularly in terms of sample digestion, can have a significant impact on the accuracy of the results obtained. Depending on the type of rock being studied and the aim of the analysis, a suitable mixture of acids should be used. The most commonly used sample digestion methods are based on a mixture of four acids (multi-acid), aqua regia and inverse aqua regia. As opposed to multi-acid whole-rock digestion, the use of aqua regia and inverse aqua regia result in only the partial digestion of sedimentary rocks. Geochemical analyses using these two different methods were carried out on Carboniferous sedimentary rocks from the Lublin Coal Basin from Poland.The elemental concentrations obtained showed essentially different results for some of the elements. A comparison of the elemental concentrations allowed the distinction of three groups of elements:
- those that showed small differences between the results from the preparation methods (Co, Mn, Bi, Cu, Zn and Fe),
- those where the elemental concentrations were 20–50% lower using aqua regia digestion (i.e. Ni, P, Pb, Mg, Cd, Th, Mo, Sr),
- elemental concentrations that were significantly lower (by up to 80%) following aqua regia digestion (U, Cr, Ba, Na, V, Al, Rb, K, Zr).
The potential of organic wastes in Ukraine for biogas production and the prospects of using the family-type biogas plants for this purpose are shown. In the biogas laboratory of the Ukrainian National Forestry University the efficiency of the anaerobic mesophilic digestion of chicken manure of Poltava poultry farm, Kamianets-Podilsky poultry farm and sewage sludge from Lviv wastewater treatment plant (WWTP) was investigated. Different integral indicators of the biogas production and significantly different dynamics of its formation over time were obtained for three investigated substrates. The value of average specific biogas production from the sewage sludge of Lviv WWTP is 0.494 dm3∙(day∙kg FM)–1, which is 5.1 times more comparing the chicken manure of Kamianets-Podilsky poultry farm and 8.0 times more than for the chicken manure of Poltava poultry farm. Strong negative effect of antibiotic treatment of chickens on methane contentin the obtained biogas was established experimentally.
Anaerobic digestion (AD) is an adequate alternative to treat wastewater generated from fruit and vegetable processing (FVWW); likewise, in recent years, artificial wetlands (AWs) have been applied as a post-treatment process for anaerobi-cally pre-treated wastewater. The objective of this work was to design a sustainable treatment system for FVWW composed of upflow anaerobic reactors (UASB) with phase separation and an AW system that receive the anaerobically pretreated effluent. Using the design methodologies for the UASB reactors and artificial wetlands with sub-surface flow (AW-SSF), the parameters of the combined AD-AW system that treat a wastewater flow of 300 m3∙d–1 were calculated. The UASB acidogenic system was adjusted to a hydraulic retention time (HRT) of 10 h and organic loading rate (OLR) of 13.84 kg COD m–3∙d–1; meanwhile, the methanogenic and cascade UASB reactors with OLRs of 10.0 and 3.0 kg COD m3∙d–1, and HRTs of 11 and 10 h, respectively, achieve a high COD removal efficiency (above 94%), and an overall biogas production rate of 1.53 m3 of biogas per m3 of reactor capacity per day. According to the results obtained with the theoretical design, anaerobic-wetland combined system achieves an overall efficiency greater than 98%. The wastewater treated by the pro-posed system will allow the reuse of 30% of the water used in the washing of fruits and vegetables.