PREDOMINANCE OF MALOLACTIC FERMENTATION OVER D-GLUCOSE UTILIZATION INLACTOBACILLUS-PLANTARUM AND LACTOBACILLUS-CURVATUS WINE STRAINS

Two selected wine strains of the genus Lactobacillus (L. plantarum 197 and L. curvatus 783) were tested for their ability to complete malola ctic fermentation (MLF) in a synthetic medium (PBM-broth) supplemented with L-malic acid (7.5-74.6 mM) and D-glucose (5.5-55 mM). The 24 dir ected fermentation assays, 12 for each bacterial strain, were carried out at 20-degrees-C and pH 3.5. MLF was completed (residual L-malic ac id less-than-or-equal-to 0.2 mM) in eight days in 19 of the 24 ferment ation assays, even in the presence of 74.6 mM L-malic acid or 55.5 mM D-glucose. D-Glucose utilization was generally simultaneous to MLF but was completed (residual concentrations less-than-or-equal-to 0.2 mM) only in 6 of the 24 fermentation assays. These results support the use of these strains in directed MLF assays at the very different L-malic acid and D-glucose concentrations tested.