Optimization of solid-state fermentation parameters for the biocontrol strain Trichoderma koningiopsis T-51

Abstract:

[Background] Trichoderma spp. have been widely used for controlling plant diseases. Trichoderma koningiopsis T-51, an effective biocontrol strain, is capable of promoting plant growth, inducing plant systemic resistance, and controlling plant diseases, demonstrating a promising prospect for practical applications. [Objective] To study and optimize the solid-state fermentation technology of T. koningiopsis T-51 for improving the spore production, and provide a theoretical reference for the large-scale production of this strain. [Methods] Single-factor experiments and response surface methodology were employed to screen the suitable fermentation substrate for strain T-51 and optimize the key fermentation factors including water content, fermentation duration, inoculation concentration, and carbon and nitrogen source composition. [Results] With rice husk as the fermentation substrate, the strain demonstrated the highest spore production. The water content of 75% and fermentation duration of 11 days significantly increased the spore production. In addition, an inoculation concentration of 1×10⁶ CFU/mL exhibited higher spore production, while the inoculation concentration of 1×10⁸ CFU/mL showed a decrease in sporulation. Glucose and ammonium sulfate were identified as the optimal carbon and nitrogen sources, respectively, for the spore production of strain T-51 with rice husk as the substrate. The fermentation parameters were optimized by the response surface methodology as water content of 79.5%, fermentation duration of 11 days, inoculation concentration of 1×10⁶ CFU/mL, 2.6% glucose, 0.75% lactose, and 5% ammonium sulfate. Under these optimized conditions, strain T-51 was predicted to achieve the maximum spore production of 7.76×10⁹ CFU/g, and the measured value was 7.83×10⁹ CFU/g. [Conclusion] This study has successfully established an efficient solid-state fermentation technology for strain T-51 with rice husk as the substrate, allowing adequate sporulation for field applications with reduced production costs. This study provided a theoretical basis for the future large-scale application of strain T-51 in the field.