SHuffle express (E. coli B) cells (C3028, C3029, C3030) will grow in minimal media, while SHuffle (E. coli K12) is an auxotroph and will require the addition of Isoleucine and Leucine (50 ug/ml) for growth in minimal media. 100X stock solutions of Ile/Leu can be made by dissolving 5 mg/ml of the amino acids in water and filter sterilizing the solution.