Effect of aeration conditions on aldehyde dehydrogenase activity in yeast cultivation

Mathematical modelling of the dehydrogenase catalyzed hexanol oxidation with coenzyme regeneration by NADH oxidase

“…It is also important to mention that during the permeabilization process, low molecular weight molecules are removed from the cells and by so doing the possibility of the unwanted side reactions is reduced [20]. In the yeast cells, enzyme alcohol dehydrogenase is responsible for the reverse reaction of the acetaldehyde reduction [21]. Besides hexanal, the only product that could be expected, by using the permeabilized yeast cells for the hexanol oxidation, is the hexanoic acid.…”

“…The enzyme aldehyde dehydrogenase for the hexanal oxidation needs the coenzyme, NAD + , which is also the substrate for the hexanol oxidation by YADH. But, since it has been found in the literature that in the yeast cell, the activity of AlDH is 10-100-fold lower than the YADH activity [21], the assumption was that the produced hexanal would not be completely oxidized to the hexanoic acid.…”

Oxidation of a mixture of 2-(R) and 2-(S)-heptanol to 2-heptanone bySaccharomyces cerevisiaein a biphasic system

“…Few studies on oxidation processes have been investigated (Karra-Chaabouni et al , 2002;Kometani et al , 1998;Li et al ., 2002). Moreover, descriptions of oxidation by baker's yeast are scarce.…”

“…Different strategies have been developed to perform oxidation reactions, involving either purified enzyme or whole cells (Cabral, 2001). Yeast cells can be used after a preliminary growth period (biocatalyst production) but the preparation of the biocatalyst can be simplified by using yeast cake or dehydrated yeast (Kometani et al , 1998;Maugard et al , 2001;Molinari et al , 1998). Previous studies carried out on purified enzymes revealed that at least two different enzymatic systems may be involved in the oxidation of alcohols (KarraChaabouni et al , 2002;Kometani et al , 1998;Li et al ., 2002).…”

“…Yeast cells can be used after a preliminary growth period (biocatalyst production) but the preparation of the biocatalyst can be simplified by using yeast cake or dehydrated yeast (Kometani et al , 1998;Maugard et al , 2001;Molinari et al , 1998). Previous studies carried out on purified enzymes revealed that at least two different enzymatic systems may be involved in the oxidation of alcohols (KarraChaabouni et al , 2002;Kometani et al , 1998;Li et al ., 2002). Indeed, the oxidation of (S )-secondary alcohols by baker's yeast could be catalysed by the yeast alcohol dehydrogenase (YADH), a member of the medium-chain dehydrogenase/reductase enzyme superfamily (Dickinson and Dack, 2001;Jornvall et al , 2003).…”