Dateline: A recent scientific breakthrough is drawing attention for its potential to revolutionize traditional pesticide production. A research team from the Institute of Plant Protection at the Chinese Academy of Agricultural Sciences (IPP-CAAS) has successfully developed a new solid-state fermentation technique using agricultural waste to produce Avermectin, the world's most significant bio-pesticide. The study, published in the renowned international journal Bioresource Technology, not only opens up new avenues for the valorization of agricultural waste but has also reduced the production cost of Avermectin by 8.38%.

Avermectin is a heavyweight product with a global annual demand of 5,000 tons and a market value exceeding $3 billion, and its production is exclusively dominated by China. However, the conventional liquid fermentation process has long faced a triple challenge of high energy consumption, heavy pollution, and prohibitive costs. This has, to some extent, limited its broader application in modern sustainable agriculture.

To tackle this challenge, the research team turned its attention to common agro-industrial wastes, such as wheat bran, corncobs, sugarcane bagasse, and even vermicompost. Through meticulous experimental design and component optimization, they identified the optimal substrate formula for solid-state fermentation. The study further revealed that substrate moisture content and oxygen supply are two key factors determining the success of the fermentation. Peak efficiency was achieved at a substrate moisture content of 78.5% and an inoculum size of 25%.

In a further breakthrough, the team explored a shallow-tray continuous fermentation strategy. This strategy can support at least four stable, repeated batches of production, not only significantly shortening the fermentation lag phase but also boosting the yield of the key active component, Avermectin B1a, to 3.83 mg/gds (grams of dry substrate). Overall calculations show that the cost of this new process is 8.38% lower than that of traditional liquid fermentation. Furthermore, the research indicates that the solid-state fermentation product itself has the potential to be used directly as a microbial pesticide, which could further simplify the application process.

This achievement is not only a major innovation in the green biomanufacturing model for Avermectin but also provides a valuable reference for the environmentally friendly production of other natural product pesticides derived from Streptomyces. The study was reportedly co-supervised by Researcher Li Shanshan of IPP-CAAS and Professor Xiang Wensheng of Northeast Agricultural University, with PhD student Du Guozhong as the first author. It received support from various funding sources, including the National Key R&D Program of China.