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Utilization of Supercritical Fluid Extraction for Botanical Insecticide Isolation
Sajfrtová, Marie ; Sovová, Helena ; Karban, Jindřich ; Pavela, R.
The aim of this study was to compare the insecticidal activity of extracts obtained by SFE and traditional extraction methods from 20 plants. Three types of extracts were prepared using the benefit of variable solvent power of supercritical carbon dioxide. The extracts rich in essential oil or oleoresin were obtained at 50 °C and 12 or 28 MPa, respectively. The extract enriched with polar components was extracted at pressure of 28 MPa with ethanol added to CO2 as modifier. Essential oils were isolated from the herbs by hydrodistillation and oleoresins were obtained using Soxhlet extraction with liquid solvents. The biological activity of extracts was measured on different kinds of insect by means of contact toxicity test (LD50, LD90) and antifeedant activity. The insecticidal activity of the SFE products was compared with conventional extracts.
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Enzymatic Reactions in Supercritical CO2
Rochová, Kristina ; Sovová, Helena ; Zarevúcka, Marie
Enzymatic hydrolysis of black current seed oil was carried out in supercritical CO2 (sc-CO2), in continuous flow reactor packed with immobilized enzyme Lipozyme. Black currant seed (Ribes nigrum L.) is rich in alfa- and gama-linolenic acids, bound in triacylglycerols, which have different dietetic effect. Selective hydrolysis allows preparation of fractions with different ratio of the two acids. Effect of reaction conditions (T=30–40°C, P=10-28 MPa) on reaction kinetics, composition of reaction mixture, selectivity and stability of enzyme. Results showed good stability of Lipozyme in sc-CO2. Alfa-Linolenic acid was unbound preferably due to enzyme stereospecificity. Combination of supercritical extraction with enzymatic reaction of extracted oil and subsequent fractionation of reaction mixture in two separators was tested in order to separate desired compounds. Further, stability of several enzymes prepared in our laboratory was tested in sc-CO2.
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Fluidized Bed Gasification of Flax used for Phytoextration of Heavy Metals
Pohořelý, Michael ; Šyc, Michal ; Jeremiáš, Michal ; Vosecký, Martin ; Kameníková, Petra ; Skoblia, Sergej ; Svoboda, Karel ; Punčochář, Miroslav
This study was aimed at determination of distribution of heavy metals among producer gas and individual size fractions of ash matter, i. e. bed ash and cyclone ash, formed in fluidized bed steam biomass gasification. Knowledge of distribution of heavy metals is necessary for further utilization of all products of the gasification.
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