Abstract:The ratio of available nitrogen source to slow release nitrogen source in erythromycin industrial fermentation medium were optimized under the condition of equal proportion of total nitrogen. Meanwhile feather peptone was tentatively used as a new type of available nitrogen source. The experimental results showed that, when the optimal ratio of available nitrogen source to slow release nitrogen source was 3.9, (the concentration of feather peptone 6 g/L and the soybean meal 33 g/L),erythromycin titer reached to 11 059 U/mL. Compared with corn steep liquor, feather peptone has the characteristic of stable quality, thus erythromycin titer fluctuation caused by quality instability of corn steep liquor can be avoided. Using the optimized medium, the traditional pH-feedback glucose feeding was compared with pH-RQ-feedback glucose feeding. The results showed that the erythromycin titer reached to 11 915 U/mL with pH-RQ-feedback glucose feeding, which was 7.7% higher than that with the traditional pH-feedback glucose feeding, moreover the total glucose amount fed to fermenter was decreased by 40%.