66.5 ml distilled water 10 ml 10x S-base 2.5 ml 20% (w/v) glucose 5 ml 0.1% (w/v) L-tryptophan 1 ml 2% (w/v) casein 5 ml 10% (w/v) yeast extract (Difco) 10 ml 8% (w/v) arginine 0.4% histidine autoclave all components separately tryptophan solution: sterile filtration