Glucose M9Y

Glucose M9Y medium, used to cultivate E. coli, is a minimal medium formulation supplemented with yeast extract. This medium is made without animal products and certified “animal product free” (APF). It is based on M9 salts with a pH of 6.9±0.2 and employs glucose as the carbon source. Alternative carbon sources may be substituted. Buffering is provided by a sodium-potassium phosphate system. Ammonium chloride provides a nitrogen source. Yeast extract is added to improve the protein production capacity of the medium and to permit cultivation of auxotrophic strains by supplying a source of amino acids, vitamins and minerals. This differs from the traditional formulation of glucose M9, which employs casamino acids. Yeast extract typically gives higher yields of recombinant proteins than casamino acids. Formula (g/l): 6.0 g sodium phosphate dibasic; 3.0 g potassium phosphate monobasic extract; 1.0 g ammonium chloride; 0.5 g sodium chloride; 4 g glucose; 5 g yeast; 11 mg calcium chloride; 241 mg magnesium sulfate.