Achieving Maximal Production of Fusaricidins from Paenibacillus kribbensis CU01 via Continuous Fermentation

In this study, we investigated the potential of Paenibacillus kribbensis CU01 in producing fusaricidin, a strong antifungal substance, via optimization of metal ions and carbon and nitrogen source, and continuous fermentation. In the cultivation of a 2-l batch, maximal production of fusaricidins (581 mg l^-1) was achieved in a modified M9 medium containing metal ions, 10 g l^-1 glucose, and 1 g l^-1 ammonium chloride. Most of glucose was consumed at a rate of 0.74 g l^-1 h^-1 within 24 h and fusaricidin production began 15 h after batch cultivation. Continuous fermentation was performed using a 7-l fermenter with 2-l working volume of modified M9 medium containing 10 g l^-1 glucose, 1 × 10^-3 M FeSO₄, and 1 × 10^-6 M MnCl₂. After 24 h of the start of cultivation, fresh M9 medium was continuously supplied at a flow rate of 2.5 ml min^-1, and simultaneously, the same amount of cell culture broth was removed. In a continuous system, the highest fusaricidin concentration (579 mg l^-1) was obtained using a dilution rate of 0.075 h^-1 with an average productivity of 10.4 mg l^-1 h^-1 for 24 to 72 h of incubation. Based on these results, it was found that fusaricidin production using P. kribbens CU01 strain increased by at least 28 times the values reported in previous studies.