Application of uniform design in L-isoleucine fermentation.

Uniform design was employed in our experiments for testing the effects of nine different compositions of the culture media for the production of L-isoleucine in Corynebacterium crenatum A11 fermentation. The most favorable medium was found to be composed of glucose 12%, (NH4)2SO4 2%, KH2PO4 0.1%, K2HPO4 0.45%, MgSO4.7H2O 0.055%, biotin 1 microgram, thiamine 20 micrograms, FeSO4.7H2O 2 ppm, MnSO4.4H2O 2 ppm, CaCO3 4% with pH 7.0-7.2. By using such medium, the amount of L-isoleucine produced by A11 was increased up to 15.1 mg/ml. Uniform design, as compared with orthogonal design, has the advantages of higher efficiency and easier analysis of the factors that affect the production.