Development of a tool based on untargeted metabolomics for the evaluation of the dissipation time of a complex biocontrol product in soil

Biopesticides are complex substances derived from natural sources. They are promoted as prospective alternatives to synthetic pesticides because they are considered to be less harmful to the environment and human health compared to chemical pesticides. However, it is still unknown how long biopesticides and their residues remain in the environment. Also, no methodologies are available to determine the fate of these biopesticides (complex mixtures). It is why, we proposed a new parameter, the dissipation time, that corresponds to the degradation of the biopesticide ingredients, i.e. the active substances and the co-formulants. It required a huge data processing.

These new developments are based on the EMF (Environmental Metabolic Footprinting), an approach recently set up in the CRIOBE Research Unit, where the meta-metabolome (xenometabolome + microbial metabolites) is investigated. In this study, the meta-metabolome data were handled in order to extract the biopesticide component metabolites from this complex dataset. Dissipation modelling was then performed on each biopesticide feature in order to predict the bio-solution dissipation time. In order to develop this concept, the fate of a bioherbicide, Beloukha (a plant extract containing formulating agents), in soil was investigated over a kinetics of 57 days. Using these models, different definition can be used for the dissipation time; we found that 94.9 % of metabolites have half-lives below 19 days and 94.9 % of metabolites have time degradation of 99% of their initial quantity below 125 days. This new approach is really useful where biopesticides are increasingly used and where regulatory methodologies are lacking.