Naslov
Study of solvent hydrophobicity on lipase catalysed reaction esterification

Autori
Giacometti, Jasminka ; Milin, Čedomila ; Vasić-Rački, Đurđa ; Giacometti, Fabio

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
The 5th International Symposium on Biocatalysis and Biotransformation (Biotrans 2001) : abstracts / Fessner, Wolf-Dieter - Darmstadt : Gesselschaft Deutscher Chemiker, 2001, 211-211

Skup
International Symposium on Biocatalysis and Biotransformation (5 ; 2001)

Mjesto i datum
Darmstadt, Njemačka, 02.09.2001. - 07.09.2001

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
enzymatic esterification; solvent hydrophobicity; lipase

Sažetak
In an organic reaction medium enzymes display several interesting properties like enhanced (thermal) stability and different substrate and stereospecificitiesƒË1ƒÍ. Enzyme activities were performed at fixed substrate concentration and comparisons of the observed rates were made under examined conditionsƒË2ƒÍ. The effect of hydrophobic organic solvents, versus log P value, was studied in lipase catalysed esterification in a batch stirrer-tank reactor (BSTR). The reactions were carried out in equimolar ratio of glycerol and oleic acid and catalyzed by 6.67 mg/ml immobilized Mucor miehei lipase in a solvent system withƒË3ƒÍ and without molecular sieves. In the solvent system with molecular sieves, the temperature effect was determined. The assay of enzyme reaction was performed by measurement with the pH-stat method and simultaneously monitored by the chromatographic determination of oleic acid, monoolein and diolein. The reactions were followed by the determination of reaction conversions during 45 h. The differences in reaction rates were an effect of solvation or partitioning of the substrate and products. The solvents with log P ƒŽ 3 (cyclohexane, heksane and isooctane) were most suitable for esterification of glycerol and oleic acid. The change of the system hydrophobicity, by using the tested solvents in the system with molecular sieves, influenced the initial rate conversion but had no effect on the final conversion. The lower log P showed higher differences in the concentration of mono- and diolein. The initial reaction rate of diolein production was higher but final monoolein concentrations were higher in all experiments. Solvent hydrophobicity had the same effect in the system without molecular sieves, but final conversions were lower.

Izvorni jezik
Engleski

Znanstvena područja
Farmacija, Prehrambena tehnologija

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