Naslov
Coenzyme regeneration in the hexanol oxidation catalysed by alcohol dehydrogenase

Autori
Vrsalović Presečki, Ana ; Vasić-Rački, Đurđa

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

Izvornik
8th International symposium on biocatalysis and biotransformations 8-13 July 2007, Biotrans 2007, Oviedo (Spain) / - , 2007, P-105

Skup
Biotrans 2007

Mjesto i datum
Oviedo, Španjolska, 08.07.2007. - 13.07.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
alcohol dehydrogenase; baker's yeast; oxidation; modelling

Sažetak
The use of the NAD+ or NADP+ dependent dehydrogenase in the organic synthesis is limited by the price of coenzyme, since it should be add in a stochiometric amount. So it is necessary to provide an efficient and economical cofactor regeneration system. [1]. There are various methods available for this purpose, but the most often used are the enzymatic one. Enzymatic ways of coenzyme regeneration include the addition of second enzyme to the system or the addition of the co-substrate. In this work both methods of enzymatic coenzyme (NAD+) regeneration were studied and compared in the reaction of hexanol oxidation catalyzed by alcohol dehydrogenase (ADH). As a source of ADH, commercial isolated enzyme and the whole baker's yeast cells were used. Since the enzyme activity in the whole cell was very low, the cells were permeabilized by detergent CTAB. The first method of regeneration was NAD+ regeneration in the reaction of pyruvate reduction catalyzed by L-lactate dehydrogenase (Figure 1A-B). The second regeneration method was coenzyme regeneration in the reaction of acetaldehyde reduction catalyzed by the same enzyme which catalyzes the main reaction (Figure 1C-D). The product of hexanol oxidation catalyzed by isolated ADH was hexanal, while the hexan acid was detected as a product of the same reaction catalyzed by permeabilzed baker's yeast cells. In the case of whole cells produced hexanal was oxidized by the action of aldehyde dehydrogenase, the enzyme that is also a part of the yeast cell. All used biocatalysts were kinetically characterized. The mass reactions were described by the mathematical models which consisted of kinetic and balance equations. All models were validated in the batch reactor. 100 % hexanol conversion was obtained using permeabilized yeast cells with both methods of cofactor regeneration. By using isolated enzyme ADH, the higher conversion was achieved in a system with cofactor regeneration catalysed by L-LDH.

Izvorni jezik
Engleski

Znanstvena područja
Drvna tehnologija

POVEZANOST RADA