Ionos folyadékokban lejátszódó enzimatikus észterezési reakciók vizsgálata integrált rendszerben = Study of enzymatic esterification reactions in ionic liquid media in integrated system

Nem konvencionális közegként ionos folyadékokat (zöld oldószereket) alkalmazva vizsgáltunk két enzimkatalitikus reakciót (rövid szénatomszámú alkoholok és savak észterezése valamint a 2-klór-propionsav enantioszelektív észterezése). Megállapítottuk, hogy az ionos folyadék alkalmas megválasztásával növelhető az alkalmazott lipáz enzimek aktivitása, enantioszektivitása és fokozható termikus stabilitása a korábban alkalmazott szerves oldószerekhez képest. A reakciótermékek eltávolítása után az alkalmazott lipáz enzimek az ionos folyadékban visszamaradtak és minimális aktivitás veszteséggel újra felhasználhatók voltak. Az enzimek tulajdonságait legerősebben befolyásoló paraméter a reakcióelegy víztartalma volt. Mivel az észterezési reakció során víz keletkezik, a bioreaktorhoz kapcsolt pervaporációs berendezéssel megoldottuk a reakcióelegy víztartalmának állandó értéken tartását. Az irodalomban elsőként ismertettük az így kialakított integrált rendszert, annak működési paramétereit, az enzimek tulajdonságaira gyakorolt kedvező hatását és a továbblépés lehetséges irányait. | Ionic liquids (green solvents) - as non-conventional media - were applied for investigation of two enzyme catalytic reactions: esterification of short chain alcohols and acids, and enantioselective esterification of 2-chloro-propionic acid. It was found that activity, enantioselectivity and thermo-stability of lipase enzymes could be enhanced - compared to the organic solvents used earlier - by using carefully selected, suitable ionic liquids. Having removed the reaction products, lipase enzymes remained in the ionic liquid and could be reused with a minimal activity lost. The water content of the reaction mixture had the strongest effect on the behaviour of the enzymes. Since water is produced during the esterification reaction, a pervaporation cell was connected to the bioreactor and water content of the reaction mixture was managed to maintain at a constant level. The integrated system constructed was presented as a new, original result in a paper, moreover the operational parameters, the favourable effects on the enzymes and the potential future trends were published, as well

Upotreba patočnog ulja, nusproizvoda prehrambene industrije u biotehnologiji - Kinetički model enzimske esterifikacije izoamilnog alkohola s oleinskom kiselinom pomoću lipaze B iz plijesni Candida antarctica

Fusel oil is a by-product of distilleries, its main component is i-amyl alcohol, which can form ester compounds. Esterification of oleic acid and i-amyl alcohol by Candida antarctica lipase B (Novozym 435 preparation) in n-heptane solvent was studied in this work. Ping-pong bi-bi mechanism (inhibition phenomena taken into account) was applied as a complex kinetic model. The parameters of the model were determined by numerical methods. It was found that four-parameter model fitted well with the experimental results and described properly the enzymatic reaction.Patočno je ulje („fusel oil“) nusproizvod destilacije, a njegov je glavni sastojak izoamilni alkohol čijom esterifikacijom nastaju esteri. U ovom je radu ispitana esterifikacija oleinske kiseline s izoamilnim alkoholom u n-heptanu pomoću lipaze B izolirane iz kvasca Candida antarctica (preparat Novozym 435). Primijenjen je složeni kinetički model ping-pong bi-bi mehanizma, pri čemu je uzeta u obzir pojava inhibicije. Parametri modela određeni su numeričkim metodama. Utvrđeno je da je za rezultate pokusa i opis enzimske reakcije najprikladniji model sa 4 parametra

Upotreba patočnog ulja, nusproizvoda prehrambene industrije u biotehnologiji - Kinetički model enzimske esterifikacije izoamilnog alkohola s oleinskom kiselinom pomoću lipaze B iz plijesni Candida antarctica

Fusel oil is a by-product of distilleries, its main component is i-amyl alcohol, which can form ester compounds. Esterification of oleic acid and i-amyl alcohol by Candida antarctica lipase B (Novozym 435 preparation) in n-heptane solvent was studied in this work. Ping-pong bi-bi mechanism (inhibition phenomena taken into account) was applied as a complex kinetic model. The parameters of the model were determined by numerical methods. It was found that four-parameter model fitted well with the experimental results and described properly the enzymatic reaction.Patočno je ulje („fusel oil“) nusproizvod destilacije, a njegov je glavni sastojak izoamilni alkohol čijom esterifikacijom nastaju esteri. U ovom je radu ispitana esterifikacija oleinske kiseline s izoamilnim alkoholom u n-heptanu pomoću lipaze B izolirane iz kvasca Candida antarctica (preparat Novozym 435). Primijenjen je složeni kinetički model ping-pong bi-bi mehanizma, pri čemu je uzeta u obzir pojava inhibicije. Parametri modela određeni su numeričkim metodama. Utvrđeno je da je za rezultate pokusa i opis enzimske reakcije najprikladniji model sa 4 parametra

Application of Ionic Liquids in the Utilization of the Agricultural Wastes: Towards the One-Step Pre-Treatment and Cellulose Hydrolysis

Cheap, renewable lignocellulosic materials are relevant to the future of biofuel production. Wood and agricultural wastes (e.g. straw, corn stover) provide a raw material source that cannot be used for human consumption, thus biofuels from such sources do not threaten the food supply. The aim of the work was to carry out the pre-treatment and hydrolysis of lignocellulosic material in the same ionic liquid solvent (1-n-butyl-3- methyl-imidazolium-chloride, [Bmim]Cl), using ground wheat straw and a mixture of corn (Zea mays) leaf and stover, as substrates. Our measurements show that it is possible to achieve an acceptable glucose content from the cellulose by applying Cellic® CTec2 and Cellic® HTec2 enzyme complexes

Enzyme kinetics approach to assess biocatalyst inhibition and deactivation caused by [bmim][Cl] ionic liquid during cellulose hydrolysis

The aim of this work was to study the inhibition and deactivation of commercial enzyme cocktail (Cellic® Htec2) in the presence of [bmim][Cl] ionic liquid employing model cellulosic substrate, carboxymethyl cellulose (CMC). It turned out from the experiements – relying on enzyme kinetics appproach – that [bmim][Cl] could act as a competitive inhibitor. Furthermore, depending on the process conditions i.e. contact of enzyme solution with high concentration [bmim][Cl], severe biocatalyst inactivation should be also taken into account as a potential risk during the enzymatic cellulose hydrolysis even in as short process times as few minutes

Micropillar Compression Study on the Deformation Behavior of Electrodeposited Ni–Mo Films

The influence of Mo addition on the compression behavior of Ni films was studied by micropillar deformation tests. Thus, films with low (0.4 at.%) and high (5.3 at.%) Mo contents were processed by electrodeposition and tested by micropillar compression up to the plastic strain of about 0.26. The microstructures of the films before and after compression were studied by transmission electron microscopy. It was found that the as-deposited sample with high Mo concentration has a much lower grain size (~26 nm) than that for the layer with low Mo content (~240 nm). In addition, the density of lattice defects such as dislocations and twin faults was considerably higher for the specimen containing a larger amount of Mo. These differences resulted in a four-times higher yield strength for the latter sample. The Ni film with low Mo concentration showed a normal strain hardening while the sample having high Mo content exhibited a continuous softening after a short hardening period. The strain softening was attributed to detwinning during deformation

Asymmetric Lactic Acid Esterification with Biocatalysts in Ionic Liquid

Biodegradability and environmentally friendly technologies recently came into prominence; this is the reason why we assayed to develop a new “green” technology for L-lactic-acid (LLA) production. Racemic lactic acid (rLA) mixture produced by chemical industry is difficult to handle. The product of esterification with low carbon chain alcohols has higher volatility than lactic acid (LA) itself, therefore it can be more effectively separated. Our reactions were carried out with biocatalysts (enzymes) — some of them prefer reactions with L-enantiomer — result in enantioselective esterification. After LLA ester production the hydrolysis leads to separated LLA, which is the starting material of a biodegradable plastic. Our aim was to achieve enantioselectivity in phosphonium-type ionic liquid solvents by the optimization of several parameters, such as temperature, substrate molar ratio, amount of IL, water content. Reasonable results were achieved with three types (Candida antarctica, Candida rugosa, AMANO PS-IM) of lipases. The use of enzymes and ionic liquids can make the technology “greener”, where an ingredient of a biodegradable plastic can be produced. The toxic heavy metals or hazardous acids can be replaced by biocatalyst (enzymes). These intermediates are re-usable, and they work at lower temperature, than conventional catalysts, thus the operational costs can be reduced. Ionic liquids — compared with conventional organic solvents — have insignificant vapour pressure, they are non-flammable and re-usable after a purification process, furthermore they can be tailor made for a certain application. It is not negligible that the structure affects the environmental features like biodegradability or toxicity. The high lactic acid dissolving capacity is the reason why phosphonium-type ionic liquids were used. There are research teams, apply them for lactic acid extraction from fermentation broth