Preparation of a new nutrient medium for lactic acid bacteria using soybean whey as a substrate and its application for cultivation

We have developed a novel medium for the culture of lactic acid bacteria using soy whey, instead of using animal-derived materials. Soy whey was prepared by removing soy protein by the treatment with MgCl2. Various lactic acid bacteria from the culture collection (NBRC) and those isolated from commercially available fermented milk products were cultivated by using the medium based on Mg-soy whey supplemented by yeast extract (YE) and glucose (Glc) as nutrition, designated YE-Glc-Mg-soy whey medium. As a result, the new medium showed almost the same growth rate as that of the MRS medium, which is generally used for culturing lactic acid bacteria. YE-Glc-Mg-soy whey medium was also used for the isolation of lactic acid bacteria, and three Gram-positive strains producing lactic acid were isolated from some citrus fruits. The present study suggested that the YE-Glc-Mg-soy whey medium can be used for the production of fermented foods that are free of allergic substances, and suitable for the people who avoid animal-derived materials because of a religious reason or any other reasons.