Application of oxygen uptake rate and response surface methodology for erythromycin production by Saccharopolyspora erythraea

A process for efficient production of erythromycin by Saccharopolyspora erythraea using statistical designs and feeding strategy was developed. The critical nutrient components were selected in accordance with fractional factorial design and were further optimized via response surface methodology. Three significant components (ZnSO₄, citric acid threonine) were identified for the optimization study. The optimum levels of these significant variables were determined with Box–Behnken design, which were ZnSO₄ 0.039 g/l, citric acid 0.24 g/l and threonine 0.42 g/l, respectively. A novel feeding strategy based on oxygen uptake rate (OUR) measurement was developed successfully to increase the flux of erythromycin biosynthesis, in which the optimized nutrient components was fed in the 50 l stirred bioreactor when OUR began to decline at 46 h. The maximum erythromycin production reached 10,622 U/ml, which was 11.7% higher than the control in the same cultivation conditions. It was the first report to integrate physiological parameter OUR and statistical methods to optimize erythromycin production.