Characterization of Leuconostoc oenos Isolated from Oregon Wines

This study was designed to characterize isolates of Leuconostoc species from Oregon wines. Gram-positive cocci were isolated, and their biochemical properties and abilities to decompose malic acid were determined. All of the isolates were heterofermentative, catalase negative, and facultatively anaerobic and occurred in pairs and chains. They produced acid from glucose, fructose, mannose, ribose, cellobiose, trehalose, and salicin but not from sucrose or lactose. They did not produce ammonia from arginine or dextran from sucrose. They grew at pH values of less than 4 and in 10% ethanol. Most but not all strains produced lactic acid and carbon dioxide from malic acid, as determined by paper chromatography and respirometry, respectively. These malolactic bacteria were considered to be strains of Leuconostoc oenos. We compared these isolates with reference strains for relative growth at pH values of 4.0, 3.5, 3.0, and 2.8 at 22°C. The isolates were similar in their growth responses at the two highest pH levels. At pH 3.0 and 2.8, however, the strains failed to grow but revealed variable abilities to dissimilate malic acid.