Abstract
Leuconostoc oenos ML 34 cells were immobilized in 1.67% calcium alginate gels to test their ability to convert L-malic acid into L-lactic acid in wine. Activity of the immobilized cells, assayed in standard buffers, was highest at pH 4.0 and 15% ethanol (v/v), and it stayed constant for 540 min. The sequential replacement of the spent incubation medium with fresh medium gave rise to an increase in activity during the first two days and to a decrease in activity thereafter. After 36 days, the activity was 60% of the maximum. About 45% to 60% of the L-malic acid was transformed into L-lactic acid by the immobilized cells in wine, and the decrease in titratable acidity was equivalent to 50% of the L-malic acid originally present, in accordance with the mechanism of malolactic fermentation in winemaking. After stirring the gels in wine several times, the activity of the immobilized cells gradually decreased until no activity was detectable. The living cells inside the gel were 2 x 108/mL, and only 0.1% leakage occurred during use.
- Received March 1981.
- Revision received July 1981.
- Accepted July 1981.
- Published online January 1982
- Copyright 1982 by the American Society for Enology and Viticulture
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