Bacillus thuringiensis (Bt) has been regarded as a biopesticide with high efficiency and safety, while it still cannot be popularized and mass-produced because of its high production costs. In the present study, we aimed to develop a cost-effective biopesticide via the secondary use of discharged vegetable wastes as the raw fermentation medium, and the insecticidal activity of Bt strain prepared by this cheap cultivation approach was evaluated. The suitable carbon source, nitrogen source additives and optimal metal ions were screened by the single-factor test, and the optimal combination of additives was determined by orthogonal test and ANOVA analysis. We found that soluble starch (6 g l⁻¹), soya bean meal (6 g l⁻¹), Al³⁺ (0.4 g l⁻¹) and Fe²⁺ (0.4 g l⁻¹) were the optimal exogenous additives, and the optimal fermentation conditions were as follows: pH 7.0, temperature of 35°C and aeration of 80 ml/250 ml. Meanwhile, the bioactivity test results showed that the Bt strain prepared by cheap cultivation still exhibited a good insecticidal effect on Helicoverpa armigera compared with the standard LB medium. Collectively, our findings provided a new strategy for vegetable waste utilization with less environmental impact and reduced production cost.

苏云金芽孢杆菌(Bt)一直被认为是一种高效、安全的生物农药，但由于生产成本较高，目前还无法推广和大规模生产。在本研究中，我们旨在通过二次利用排放的蔬菜废弃物作为原始发酵培养基来开发一种具有成本效益的生物农药，并对通过这种廉价栽培方法制备的Bt菌株的杀虫活性进行了评估。通过单因素试验筛选合适的碳源、氮源添加剂和最佳金属离子，并通过正交试验和方差分析确定最佳添加剂组合。我们发现可溶性淀粉（6 gl ⁻¹ ）、豆粕（6 gl ⁻¹ ）、Al ³⁺ （0.4 gl ⁻¹ ）和Fe ²⁺ （0.4 gl ⁻¹ ）是最佳外源添加剂，且最佳外源添加剂为发酵条件如下：pH 7.0，温度35℃，通气量80ml/250ml。同时，生物活性测试结果表明，与标准LB培养基相比，廉价培养制备的Bt菌株对棉铃虫仍表现出良好的杀虫效果。总的来说，我们的研究结果为蔬菜废物利用提供了一种新策略，可以减少对环境的影响并降低生产成本。