Agro-waste valorization for eco-friendly Bacillus subtilis biopesticide production through solid-state fermentation

The indiscriminate use of synthetic chemical pesticides has led to immense environmental degradation, ecological disruption and negative impacts to human health, necessitating a transition to sustainable approaches for agricultural protection. This research paper presents a systematic process design and optimization of biopesticide production using solid-state fermentation (SSF) with inexpensive agro-industrial wastes such as sugarcane bagasse and neem cake. The Box–Behnken Design (BBD) and Response Surface Methodology (RSM) were used to concurrently optimize three key process factors, each evaluated at three levels: fermentation temperature (25–37 °C), substrate pH (6.0–8.0), and incubation duration (24–72 h). The experimentally selected condition (30 °C, pH 7.0 and 48 h) gave the highest observed spore production of 7.93 × 10⁸ CFU/g, which was 3.7 times higher than under unoptimized conditions. The optimized biopesticide exhibited strong pesticidal activity against five economically important agricultural pests within 72 h. The environmental suitability and commercial feasibility of the product were confirmed by bioassay, ecotoxicological and storage stability evaluations. Furthermore, techno-economic evaluation showed 62.1% reduction in the production cost compared to the conventional chemical pesticide. This study underscores the potential of waste-to-wealth approaches to offer sustainable, circular, and economic solutions that reduce the reliance on synthetic agrochemicals, and enhance sustainable agriculture.