Abstract: The present invention discloses microbial organisms capable of fermenting malic acid to lactic acid having impaired capability of degrading citric acid. These microbial organisms are for example useful in methods of preferentially degrading malic acid over citric acid in a liquid composition or in methods of inducing malolactic fermentation during wine production. The invention also discloses a concentrate of these microbial organisms and methods of preparing such a concentrate. The present invention furthermore relates to an activation solution useful for incubation of microbial organisms prior to inoculation into a liquid composition, such as wine.