NUCEL® 581 PW is suitable for a broad range of mesophilic and thermophilic lactic bacteria, NuCel® 581 PW associated with yeast extract promotes microorganisms growth and can be used during the strain conservation as viability protective agent. NuCel® 581 PW is a primary yeast peptone obtained by the autolysis of a selected strain of yeast, especially grown on a molasses-based media.