Abstract:

To address the challenges in the industrialization of Trichoderma-based biofungicides, including high liquid fermentation costs, low spore yields, and extensive solid-state fermentation processes, this study aimed to achieve cost-effective, high-efficiency conidia production of the plant growth-promoting and antagonistic strain Trichoderma citrinoviride HT-1. Using agricultural wastes as solid fermentation substrates, we systematically optimized the substrate composition and fermentation conditions through single-factor experiments, orthogonal array design, and response surface methodology. The growth-promoting effects of the fermented product were further evaluated on wheat and tomato seedlings in pot experiments. The optimal solid substrate formula was maize straw : wheat bran : peanut shell : cottonseed hull = 2 : 2 : 3 : 1. The key fermentation parameters were inoculum size (14.22%), moisture content (48.89%), and fermentation duration (13.27 days). Under these optimized conditions, strain HT-1 achieved a maximum spore yield of 1.01 × 10¹¹ spores/g. Pot experiment results showed that the fermented product significantly increased plant height, root length, fresh weight, and dry weight of both wheat and tomato seedlings (P < 0.05). Collectively, this study establishes a stable, high-yield solid-state fermentation technology for T. citrinoviride that enables the valorization of agricultural wastes. These findings provide a scientific basis and technical support for the industrial development and green agricultural application of T. citrinoviride HT-1. Future research should focus on formulation development, field stability testing, and mechanistic studies of plant growth promotion.

Key words: Trichoderma citrinoviride, solid-state fermentation, agricultural waste, conidia, response surface methodology, growth-promoting effect