WL (Walerstein Laboratory) media follow the formula described by Green and Gray for the examination of materials related to brewing and for industrial fermentations containing mixed flora of yeasts and bacteria. Yeast extract is a source of vitamins, amino acids and trace elements. Casein enzymic hydrolysate provides nitrogen, amino acids and carbon. Dextrose is the main carbon and energy source. Potassium phosphate is the buffering agent. Several salts in the medium provide essential ions and help to maintain osmotic balance. Bromcresol green acts as pH indicator and agar as solidifying agent. WL Nutrient Agar is used for the examination of materials encountered in brewing and for industrial fermentations containing mixed flora of yeasts and bacteria.
