Advancing mycotoxin degradation in agricultural waste: insights from Hermetia illucens larvae and frass safety analysis

The use of insects to transform low-value organic waste into high-protein products is an innovative approach to addressing agricultural waste challenges. This study explored the bioconversion of naturally mycotoxin-contaminated bean seed residues by Hermetia illucens larvae, emphasizing the quantification of mycotoxin (entomo)degradation and the safety evaluation of frass as an organic fertilizer. UHPLC-MS/MS was employed to measure changes in mycotoxin concentrations during larval bioconversion and subsequent aerobic maturation of frass. The larvae demonstrated efficient utilization of dry bean seed biomass (approx. 67%) and were found to completely degrade deoxynivalenol, monoacetoxyscirpenol, diacetoxyscirpenol, and T-2 toxin, alongside a measurable reduction in nivalenol. Accurate quantification revealed increased levels of HT-2 toxin, zearalenone, and its metabolites (α-zearalenone and β-zearalenone) in raw frass, which were not present in the original substrate. Further measurement of matured frass indicated elevated concentrations of HT-2 toxin and zearalenone, coupled with a reduction in α- and β-zearalenone. No bioaccumulation of any tested mycotoxins was detected in larvae or pupae, as confirmed through measurement protocols. This research highlights the ability of H. illucens to process hazardous agricultural residues into safer, resource-efficient organic fertilizers, aligning with global efforts to enhance the utilization of unique abilities of insects in not only sustainable food and feed systems but also circular biowaste management.