Utilization of glucose, fructose and malic acid by malolactic bacteria: effect of ethanol and formation of mannitol and volatile acids

Five lactic acid bacteria capable of carrying out the malolactic fermentation were studied at 15°C and 25°C. Results indicated that at 15°C hardly any glucose, fructose and l ‐malic acid was utilized over a 9d period. After 9d at 25°C very little glucose and fructose and most (if not all) of the l ‐malic acid was degraded. The addition of ethanol markedly affected the l ‐malic acid utilization by the four Leuconostoc oenos strains at 25°C. Large differences in their ability to convert l ‐malic acid were found amongst the four strains in media containing 5% and 10%(v/v) ethanol.