Enhanced antibiotic activity of Xenorhabdus nematophila by medium optimization.

Nutrition had highly influence on the antibiotic production by Xenorhabdus nematophila YL001. Glucose and peptone were identified as the best carbon and nitrogen sources that significantly affected antibiotic production using one-factor-at-a-time approach. Response surface methodology was applied to optimize the medium constituents (Glucose, peptone and minerals) for antibiotic production by X. nematophila YL001. Higher antibiotic activity (328.9 U/ml) was obtained after optimizing medium components. The optimal levels of medium components were (g/l): glucose 6.13, peptone 21.29, MgSO(4).7H(2)O 1.50, (NH(4))(2)SO(4) 2.46, KH(2)PO(4) 0.86, K(2)HPO(4) 1.11 and Na(2)SO(4) 1.72. An overall 16% and 35% increase in antibiotic activity were obtained as compared with mean observed response (283.7U/ml) at zero level of all variables and YSG medium.