title: Effects of alcohols on the respiration and fermentation of aerated suspensions of baker's yeast.
abstract: The immediate effects of externally added alcohols on CO2 production and O2 consumption of suspensions of washed, aerated baker's yeast were studied by stopped-flow membrane inlet mass spectrometry. Glucose-supported fermentation was progressively inhibited by increasing ethanol concentration (0-20%, v/v). The inhibition by ethanol was quite different from that observed for acetaldehyde; thus it is unlikely that toxicity of the latter can account for the observed effects. For five different alkanols (methanol, ethanol, 1-propanol, 2-propanol and 1-butanol) increasing inhibition of anaerobic fermentation was correlated with increased partition coefficients into a hydrophobic milieu. This suggests that the action of ethanol is primarily located at a hydrophobic site, possibly at a membrane. Results for respiratory activities were not as definite as for those for anaerobic metabolism because some alkanols act as respiratory substrates as well as giving inhibitory effects.
authors.affiliation: Institute of Biochemistry, Odense University, Denmark.
authors.forename: H N
authors.initials: HN
authors.lastname: Carlsen
authors.forename: H
authors.initials: H
authors.lastname: Degn
authors.forename: D
authors.initials: D
authors.lastname: Lloyd
mesh_terms: D000332:Aerobiosis; D000438:Alcohols / Q000494:pharmacology*; D000693:Anaerobiosis; D002245:Carbon Dioxide / Q000378:metabolism; D005285:Fermentation / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism; D007700:Kinetics; D010101:Oxygen Consumption / Q000187:drug effects*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000438:Alcohols; D002245:Carbon Dioxide; D005947:Glucose