Development of a new Biocontrol Agent to reduce AflaToxin B1 contamination in maize crops for sustainable agriculture – DEBAAT

This project aims to develop the first biocontrol agent (BCA) from bacterial origin to effectively control aflatoxin B1 (AFB1) contamination of maize crops. AFB1 is a human carcinogenic mycotoxin produced by Aspergillus flavus, a filamentous fungus, emerging on maize in Europe and in France in response to climate change. Currently, crop protection against filamentous fungi mostly relies on the use of chemical inputs as antifungal agents, but none of them guarantees an efficiency against AFB1 contamination. We have selected actinobacterial strains for their ability to produce extracellular metabolites recovered in cell free supernatants (CFS) able to reduce AFB1 concentration in vitro. To propose an effective BCA, it is necessary to produce large volume of CFS, to optimize its formulation with biodegradable natural polymers and/or additives to obtain BCA microparticles and to carry out application tests of these microparticles resuspended in water, under controlled conditions in greenhouse and real conditions in the field by using a spreader drone. Indeed, the most susceptible physiological stage to A. flavus colonization is the maize ear, at which the height of the plant does not allow treatment by traditional engines.

Production of CFS on larger scale requires the optimization of the culture conditions of actinobacteria in bioreactor. For CFS formulation, natural biodegradable supports and/or additives will be tested and then dry BCA microparticles will be obtained using freeze-drying and spray-drying microencapsulation technologies. The BCA microparticles thus obtained, easy to store and transport, will be dissolved in water, to be compatible with an application with a spreader drone, which is the only engine that can be used at the most sensible physiological stage of maize plants.

This new BCA is an alternative to chemical inputs, intended for maize farmers to reduce emerging AFB1 contamination.. Thus, this new BCA could be recommended by agricultural cooperatives in charge of grain collection and regulatory analysis of mycotoxins. This would reduce human and animal health problems linked to AFB1 exposition, as well as economic losses due to contaminated raw materials.

In France, AFB1 contamination is an emerging threat in response to global warming. There are currently no biological or chemical system to limit the concentration of AFB1 in raw materials. The only authorized products do not target A. flavus, and their effect on AFB1 synthesis has never been tested. DEBAAT offers a BCA specifically designed to reduce AFB1 production without impacting A. flavus growth, while respecting microbial ecosystems. The innovation is based on the production of BCA microparticles that can be resuspended in water and applied by spraying using a spreader drone, to treat plots at the stage when mechanical treatment is no longer possible. This BCA responds to the will to reduce chemical inputs in agriculture, to contribute to the protection of farmers' health during application due to its aqueous nature, and to reduce human/animal exposure to AFB1 as well as economic losses due to the withdrawal of contaminated batches.

This project involves two research organizations and one socio-economic partner .The LGC, coordinator of the project, has all the know-how on the implementation of BCA to control the contamination of foodstuffs by mycotoxins. The LCAI has the skills for the formulation steps. Ovalie Innovation has all the contacts to organize the agronomic tests, has a staff trained in the use of spreader drone and act as a link with future users.