Effects of ADH2 Overexpression in Saccharomyces bayanus during Alcoholic Fermentation

• Published in: Applied and Environmental Microbiology Vol. 74; no. 3; pp. 702 - 707
• Main Authors: Maestre, Oscar, García-Martínez, Teresa, Peinado, Rafael A, Mauricio, Juan C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.02.2008; American Society for Microbiology (ASM)
• Subjects: Acetaldehyde - metabolism; Alcohol Dehydrogenase - genetics; Alcohol Dehydrogenase - metabolism; Biological and medical sciences; Culture Media; Ethanol - metabolism; Fermentation; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Expression Regulation, Fungal; Glucose - metabolism; Industrial Microbiology; Microbiology; Oxidation-Reduction; Physiology and Biotechnology; Quaternary Ammonium Compounds - metabolism; Saccharomyces - classification; Saccharomyces - enzymology; Saccharomyces - genetics; Saccharomyces - growth & development; Saccharomyces - metabolism; Saccharomyces bayanus; Up-Regulation; Vitaceae; Wine - microbiology; Ascomycota; Fungi; Gene overexpression; Yeast; Saccharomyces bayanus; Alcoholic fermentation
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.01805-07

The effect of overexpression of the gene ADH2 on metabolic and biological activity in Saccharomyces bayanus V5 during alcoholic fermentation has been evaluated. This gene is known to encode alcohol dehydrogenase II (ADH II). During the biological aging of sherry wines, where yeasts have to grow on ethanol owing to the absence of glucose, this isoenzyme plays a prominent role by converting the ethanol into acetaldehyde and producing NADH in the process. Overexpression of the gene ADH2 during alcoholic fermentation has no effect on the proteomic profile or the net production of some metabolites associated with glycolysis and alcoholic fermentation such as ethanol, acetaldehyde, and glycerol. However, it affects indirectly glucose and ammonium uptakes, cell growth, and intracellular redox potential, which lead to an altered metabolome. The increased contents in acetoin, acetic acid, and L-proline present in the fermentation medium under these conditions can be ascribed to detoxification by removal of excess acetaldehyde and the need to restore and maintain the intracellular redox potential balance.