Co-culture of Trichoderma atroviride SG3403 and Bacillus subtilis 22 improves the production of antifungal secondary metabolites

In this study, the co-cultivation of Trichoderma atroviride SG3403 and Bacillus subtilis 22 was optimized for the production of antifungal metabolites. Response surface methodology was applied to establish a statistical model for optimizing the co-culture medium components and fermentation conditions. The results showed that the optimal co-culture parameters were 28 degrees C, 214 rpm, initial pH of 6.8 and a medium containing 10 g/l yeast powder and 27.6 g/l molasses. Under the optimal conditions, the fermented culture filtrate of the co-culture inhibited Fusarium graminearum by 54.22%. Furthermore, antifungal and plant growth promoting metabolites were increased in the fermented culture filtrate of co-culture compared with the monoculture. The increased production of specific antifungal and plant growth promoting components in the co-culture could enhance the biocontrol effect of Trichoderma and Bacillus, and the mixture provides an effective source for the development of bio-control agents.