“…Nitrogen Sources. Proteinaceous materials such as extracted seed meals, yeast, and concentrates such as distillers' solubles, cornsteep liquor, fish stick liquor, and meat stick liquor are favored raw materials for many fermentations, particularly riboflavin, antibiotics, and vitamin B12 (101,146,269,286,296,303,390,394,395,397,402,404,405).…”