Eight malolactic bacterial strains were isolated through enrichment cultures kept at 10°C from different Tuscan wines. Six strains were identified as Oenococcus oeni by ARDRA and species specific PCR. Two strains were tentatively assigned to L. brevis. A kinetic approach was used to assess their activity at 25° and 10°C. All strains induced a remarkable conversion of L-malate at 25°C. Four strains showed a measurable fermentative activity at 10°C, among which L. brevis LB2 gave a significant conversion of L-malate. The kinetic activity of this strain appears to be unaffected by the components dissolved in wine.