Malolactic fermentation (MLF) is an important step in wine production, and can take place spontaneously or by induction, typically after the completion of alcoholic fermentation. MLF is known to reduce unwanted acidity and produce desirable aromas in some wine styles. Wine lactic acid bacteria (LAB) used for MLF have fastidious nutritional requirements, which may not be met by wine constituents, impeding MLF. Commercial nutrient preparations are available to assist malolactic fermentation, but little is known about their exact composition and ability to support bacterial growth and performance. The aim of this study was to carry out a detailed chemical analysis of enological and malolactic nutrients, and to evaluate their effect on the growth of commercial malolactic bacterial strains. Six commercial nutrients were analyzed for moisture content, turbidity, elemental composition, free amino nitrogen (FAN), free amino acids, total amino acids, vitamins, and fatty acids. Two Oenococcus oeni and one Lactobacillus plantarum strains were used, in combination with each of the six nutrients, for growth studies under anaerobic conditions in a model wine solution. The six nutrients varied significantly in individual analytes, and both bacterial growth and the conversion of malic acid by the MLF were determined by the type of nutrient used. Keywords Malolactic fermentation (MLF), wine lactic acid bacteria (LAB), enological nutrients, malolactic nutrients, yeast extract