D3360: Solid-state fermentation of Tenebrio molitor byproducts to produce proteases and chitinases

In the current market of Tenebrio molitor, only the larval stage is commercialized for food and animal feeding purposes, while the adults and frass are by-products only used as fertilizer. Despite the high protein content of adult insects, the elevated presence of chitin hinders protein digestibility and thereof bioavailability. Nonetheless, adult insects and frass may be valorized through eco-saving processes, such as solid-state fermentation (SSF), simultaneously guaranteeing “zero wastes” generation in insect farms and the obtention of high-valued compounds. SSF is a cost-effective and green approach that widens the exploitation of highly abundant and disposable biomass, extracting molecules with beneficial and functional properties, generating economic value and applicability in diverse industrial sectors. Filamentous fungi can use solids as both physical and nutritional supports, generating a wide range of molecules, including enzymes as proteases and chitinases. These enzymes can be used to fractionate insect biomass in protein and chitin derivatives as chitosan, chito-oligosaccharydes and N-acetylglucosamine. In this study, a broad set of fungal strains were used in SSF of adult insects and frass from T. molitor, assessing the production of proteases, chitinases. The results allowed identify the fungi with potential to grow in these materials. The proteases produced will be applied to produce protein hydrolysates from insect biomass and chitinases will be applied in the production of chitosan from insect chitin. A new use for by-products of Tenebrio molitor farming has been achieved; the products obtained can be applied in the insect industry itself, helping to develop a circular economy.