Enhanced production of human epidermal growth factor under control of the phoA promoter by acetate-tolerant Escherichia coli DB15 in a chemically defined medium

摘要: The phoA expression system is an efficient one and successfully used in foreign gene expression. In a previous study, it was found that pH during the phase had significant effect on extracellular hEGF production under control of promoter by Escherichia coli DA19, acetate-tolerant strain E. DH5α, chemically defined medium, but level only 75.5 mg/L. DB15 another acetate tolerant mutant DH5α. present further investigated. When transition from growth phase, where phosphate abundant, to limited, performed based cell density, reached 165 mg/L, twice when dissolved oxygen. Furthermore, adding 0.22 g/L CaCl2 increased 228 which 3-fold produced DA19 (pAET-8) cultured same medium.