Physiological response to anaerobicity of glycerol-3-phosphate dehydrogenase mutants of Saccharomyces cerevisiae.

摘要: Mutants of Saccharomyces cerevisiae, in which one or both the genes encoding two isoforms NAD-dependent glycerol-3-phosphate dehydrogenase had been deleted, were studied aerobic batch cultures and aerobic-anaerobic step change experiments. The respirofermentative growth rates under conditions with semisynthetic medium (20 g glucose per liter) single mutants, gpd1 delta gpd2 delta, parental strain (mu = 0.5 h-1) almost identical, whereas rate a double mutant, was approximately half that strain. Upon from to anaerobic exponential phase, specific carbon dioxide evolution (CER) wild-type unchanged. mutant showed an immediate, large (> 50%) decrease CER upon conditions. However, after about 45 min increased again, although not same level as drastic fermentation transition values even exceeded levels addition acetoin. High-pressure liquid chromatographic analyses demonstrated added acetoin served acceptor reducing equivalents by being reduced butanediol. results clearly show necessity glycerol formation redox sink for S. cerevisiae