Abstract:

A four-factor, three-level orthogonal array design was employed to optimize four medium components for the production of Fusarium decemcellulare Brick inhibitor by Bacillus subtilis B26, and the effects of fermentation conditions on the production of Fusarium decemcellulare Brick inhibitor were explored through single factor experiments. The optimal medium composition for maximizing inhibition rate against Fusarium decemcellulare Brick was found to be composed of peptone 25 g/L, starch 45 g/L, sodium chloride 1.5 g/L, ammonium sulfate 1.0 g/L, and dipotassium hydrogen phosphate 1.5 g/L. Seed age of 24 h, inoculmum size of 5%, initial pH of 7, the volume of medium in the fermentation vessel of 20%, the amount of added Tween -80 of 0.5%, fermentation temperature of 30 ℃, rotational speed of 150 r/min and fermentation period of 60 h were found optimal. The inhibition circle diameter of the fermentation broth obtained under these conditions was 26 mm.

Key words: Fusarium decemcellulare Brick, biological control, orthogonal array design, fermentation conditions