Control of Malolactic Fermentation in Wine. 2. Isolation and Characterization of a New Malolactic Organism

Abstract

Several natural isolates of lactic acid bacteria were made from wines which were undergoing spontaneous malolactic fermentation. These organisms were screened for: rapid growth; rapid metabolism of malic acid; and optimal growth response to pH, alcohol, SO₂, fumaric acid, and temperature. Of the natural isolates studied, a strain designated B44·40 showed the greatest potential for rapid growth, efficient metabolism of malate, and greatest tolerences to variations of pH and temperature. When B44·40 was compared to ML-34 and PSU-1, it was found to grow more rapidly in synthetic media and to metabolize organic substrates present in wine such as malate and glucose at a more rapid rate than either ML-34 or PSU-1. B44·40, ML-34 and PSU-1 showed similar tolerances to alcohol and fumaric acid. B44·40 showed less tolerance to SO₂ than either ML-34 or PSU-1.