Abstract: By shaking flask-fermentation assay, we compared the effects of 11 media commonly used for the cycle lipopeptide production by Bacillus spp. on the Iturin A synthesis of strain CC09, and optimized fermentation conditions by using the Plackett-Burman method, the central composite design and the response surface techniques. Results showed that CC09 could produce Iturin A up to 501 mg/L under the optimal medium:wheat powder 14 g/L, soybean meal 25 g/L, corn flour 8 g/L, MgSO₄ 0.1 g/L, MnSO₄ 2.5 mg/L, FeSO₄ 0.8 mg/L; and culture condition:60 mL medium in 250 mL flask, pH 6, 28℃, 125 r/min, 48 h. Under the optimized condition, the production of Iturin A by strain CC09 is 4.2-fold higher than that by the strain fermented in LB medium (138 mg/L). Moreover, the fermentation cost under the optimal condition is about 4.9% of the cost under the modified LB medium.

Key words: Bacillus amyloliquefaciens, iturin A, medium composition, fermentation condition, response surface technique