TY - JOUR T1 - Metabolic Interactions Between <em>Saccharomyces cerevisiae</em> and <em>Leuconostoc oenos</em> in a Model Grape Juice/Wine System JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 53 LP - 60 DO - 10.5344/ajev.1986.37.1.53 VL - 37 IS - 1 AU - S. W. King AU - R. B. Beelman Y1 - 1986/01/01 UR - http://www.ajevonline.org/content/37/1/53.abstract N2 - Metabolic interactions between wine yeast (Saccharomyces cerevisiae Montrachet No. 522) and a malolactic bacterium (Leuconostoc oenos PSU-1) were investigated by comparing their growth in both pure and mixed culture in a model grape juice/wine system. Yeast inhibited early bacterial growth, and growing bacteria accelerated the death phase of the yeast growth cycle. Ornithine was not produced by the growing bacteria; thus, this compound was not responsible for the bacterial antagonism of yeast. Dilution of the grape juice from 20° to 10°Brix with water reduced antagonistic effects, making it possible to obtain both organisms in stationary phase simultaneously. Ethanol and acetaldehyde-bound sulfur dioxide were investigated as possible yeast produced bacterial inhibitors. They were added to the grape juice/wine system sequentially in levels previously determined to be produced by normal yeast growth in the juice. Ethanol stimulated early bacterial growth when concentrations were less than two percent, but inhibition of growth occurred later, when levels exceeded six percent. The low concentration of acetaldehyde-bound sulfur dioxide added (7.8 mg/L) had little effect on bacterial growth, but it did negate the early stimulation of growth by ethanol when the two compounds were added together. The most severe bacterial inhibition resulted from actual yeast growth, which indicated that the early inhibition of bacteria in the juice/wine system was more complex than the factors studied. ER -