20.500.12556/DKUM-26037 Supercritical fluids as solvents for enzymatic reactions Enzymes may act in different solvent systems. Water as the solvent in vivo may be replaced partially or mostly with other solvents, such as micro-emulsions, organic solvents, reversed micelles, ionic liquids and supercritical fluids (SCFs).Several types of enzymatic reactions were performed in SCFs. Influence of SCFs on enzyme stability and activity is presented on different examples; on different reaction systems (hydrolysis, transesterification...) and on the use of non-immobilized (Subtilisin carlsberg, Aspergillus niger...) as well as immobilized enzymes. Several types of high-pressure enzymatic reactors (batch-, stirred-tank-, extractive semibatch-, recirculating batch-, semicontinuous flow-, continuous packed-bed-, and continuous-membrane reactors) have been used for the performance of enzymatic reactions. In the studies on stability of biocatalysts in a high-pressure batch-stirred tank reactor changes in biocatalysts activity due to pressurization/depressurization steps were observed. Interesting alternative to overcome this inconvenience is the use of the high-pressure continuous membrane reactors, where just single compression and expansion step is necessary. Encimi so lahko aktivni v različnih okoljih. Vodo, kot topilo in vivo, lahko delno ali v celoti nadomestimo z drugimi topili, kot so; mikro-emulzije, organska topila, reverzni miceliji, ionske tekočine in superkritični fluidi (SCFs). V SCFs so bile izvedene mnoge encimsko katalizirane reakcije. Vpliv SCF na stabilnost in aktivnost encima je v članku predstavljen na različnih primerih; z uporabo različnih reakcijskih sistemov (hidroliza, transesterifikacija ...), z uporabo prostih (Subtilisin carlsberg, Aspergillus niger …) in imobiliziranih encimov. Za izvedbo encimsko kataliziranih reakcij se uporabljajo naslednji tipi visokotlačnih encimskih reaktorjev; šaržni mešalni, ekstrakcijski polšaržni, recirkulacijski šaržni, polkontinuirani pretočni, kontinuirani z nasutim slojem biokatalizatorja in kontinuirani membranski reaktorji. Študije stabilnosti biokatalizatorja v visokotlačnem šaržnem mešalnem reaktorju so pokazale, da se aktivnost biokatalizatorja spreminja zaradi kompresije/dekompresije po vsaki šarži. Temu se lahko izognemo z uporabo visokotlačnega kontinuiranega membranskega reaktorja. enzymatic reactions supercritical carbon dioxide high-pressure enzyme stability high-pressure reactors encimske reakcije superkritični $CO_2$ visoki tlaki stabilnost encimov visokotlačni reaktorji true false true Angleški jezik Slovenski jezik Znanstveno delo 2012-05-31 11:45:29 2012-05-31 11:45:29 2022-04-15 13:19:13 2023-12-31 03:26:36 2007 0 0 str. 667-677 št. 4 Letn. 54 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1318-0207 66-987 14086149 12002582 1318-0207 URN:SI:UM:DK:YT8WOKZB Acta_Chimica_Slovenica_2007_Habulin,_Primozic,_Knez_Supercritical_fluids_as_solvents_for_enzymatic_reactions.pdf Acta_Chimica_Slovenica_2007_Habulin,_Primozic,_Knez_Supercritical_fluids_as_solvents_for_enzymatic_reactions.pdf 1 A5A4F4950D99DEAB2EAFEB295C089E7A 4e3c5764bdfa0509973481d1c55d4af90755fe5fef02505723a30a1e08778603 1c11e337-7c07-11eb-bb7a-00155d0001ca 20.500.12556/dkum/5d0aad22-62ca-478f-ade2-db16215bd06c https://dk.um.si/Dokument.php?lang=slv&id=116047 http://acta-arhiv.chem-soc.si/54/54-4-667.pdf 1 https://dk.um.si/Dokument.php?lang=slv&id=116048 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0