Patent ID: 8053236

Claim:
A method for stabilizing a concentrated feed medium for feeding a mammalian cell culture comprising adding to the feed medium from 25 mM to 45 mM pyruvate, wherein the feed medium comprises cysteine and/or cystine, wherein the sum of the concentrations of cysteine and/or cystine is at least 7.9 mM, wherein the concentration of cysteine is not more than 40 mM and the concentration of cystine is not more than 1.4 mM, wherein the feed medium further comprises arginine at a concentration of 1-57 mM, tryptophan at a concentration of 0.2-11 mM, histidine at a concentration of 0.6-67 mM, methionine at a concentration, from 0.6-31 mM, phenylalanine at a concentration of 0.7-46 mM, isoleucine at a concentration of 1.6-80 mM, proline at a concentration of 2.6-130 mM, valine at a concentration of 2.5-128 mM, threonine at a concentration of 2.5-126 mM, serine at a concentration of 1.1-143 mM, lysine at a concentration of 2.4-165 mM, and leucine at a concentration of 2.2-115 mM, wherein the pH of the feed medium is from 5.8 to 7.4, wherein the feed medium does not comprise more than 4.4 mM tyrosine, and wherein the feed medium with the added pyruvate is stable for at least 1 week at 4-8° C.