Open AccessMolecular and physiological aspects of alcohol dehydrogenases in the ethanol metabolism of S accharomyces cerevisiae
Author(s) -
Smidt Olga,
du Preez James C.,
Albertyn Jacobus
Publication year - 2012
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2011.00760.x
Subject(s) - acetaldehyde , alcohol dehydrogenase , ethanol , biology , ethanol metabolism , biochemistry , saccharomyces cerevisiae , ethanol fuel , ethanol fermentation , fermentation , glycerol , yeast , aldehyde dehydrogenase , dehydrogenase , alcohol , metabolism , enzyme
The physiological role and possible functional substitution of each of the five alcohol dehydrogenase ( Adh ) isozymes in S accharomyces cerevisiae were investigated in five quadruple deletion mutants designated strains Q 1– Q 5, with the number indicating the sole intact ADH gene. Their growth in aerobic batch cultures was characterised in terms of kinetic and stoichiometric parameters. Cultivation with glucose or ethanol as carbon substrate revealed that Adh1 was the only alcohol dehydrogenase capable of efficiently catalysing the reduction of acetaldehyde to ethanol. The oxidation of produced or added ethanol could also be attributed to Adh1 . Growth of strains lacking the ADH1 gene resulted in the production of glycerol as a major fermentation product, concomitant with the production of a significant amount of acetaldehyde. Strains Q 2 and Q 3, expressing only ADH2 or ADH3 , respectively, produced ethanol from glucose, albeit less than strain Q 1, and were also able to oxidise added ethanol. Strains Q 4 and Q 5 grew poorly on glucose and produced ethanol, but were neither able to utilise the produced ethanol nor grow on added ethanol. Transcription profiles of the ADH4 and ADH5 genes suggested that participation of these gene products in ethanol production from glucose was unlikely.