| Solid medium formula was optimized using response surface methodology to increase the solid culture biomass of Nocardia rubra Nr-8206. First, discovered the key factors affecting the biomass of N. rubra Nr-8206 from existing medium formula by Plackett-Burman method, then determined the formula with the largest biomass adopted the steepest ascent, used as basic starting value of central composite design (CCD) experiment to fit the mathematical model equations, finally was to find the optimal combination. The optimized formula was then transferred to the enterprises to apply enlargement experiment and conduct verification and comparison of the results. The results showed that key factors that affected the biomass of N. rubra Nr-8206 in each medium component were: peptone, NaCl, and beef extract; and the optimal solid medium formula was: peptone 42 g/L, beef extract 8 g/L, NaCl 1.2 g/L, glycerol 10 mL/L, Na2HPO4·12H2O 0.3 g/L, agar 20 g/L. In terms of cell biomass, the optimal solid medium formulation was higher by 104% as compared with the original formulation. Therefore, response surface methodology can be used to optimize the solid medium for improving the biomass of N. rubra Nr-8206, and also provide a basis for the optimization of N. rubra Nr-8206 culture conditions and liquid fermentation. |
