Abstract: Based on the index of antimicrobial activity of ethyl acetate extracts from culture liquid of Bionectria ochroleuca strain Bo-1 to Xanthomonas oryzae pv. oryzae, the optimal carbon source, nitrogen source and salt for the production of antimicrobial substance by strain Bo-1 were tested by single factor experiments. The medium composition and fermentation conditions were optimized by orthogonal experiments. The results showed that the optimal carbon source, nitrogen source and salt were starch, peptone, MgSO4?7H2O, respectively. The optimal composition of the medium was 30 g/L starch, 2 g/L peptone, 0.5 g/L MgSO4?7H2O. The optimal fermentation conditions were the combination of temperature 30℃ , agitation speed 150 r/min, medium volume 80 mL/250 mL, initial pH6.5.

Key words: Bionectria ochroleuca, Orthogonal experiments, Fermentation, Optimization, Antimicrobial activity