Potential use of frass from edible insect Tenebrio molitor for proteases production by solid-state fermentation
Nuno Muñoz-Seijas, Helena Fernandes, David Outeiriño, María Guadalupe Morán-Aguilar, José Manuel Domínguez, José Manuel Salgado
Abstract
Novel, eco-saving and low-cost food sources are a global priority, such as edible insects. This work sets a valorization pathway for frass and Tenebrio molitor adult insects using solid-state fermentation (SSF) to obtain fungal proteases. Initial screening experiments demonstrated that Aspergillus uvarum MUM 08.01 was the most efficient proteases producer. Small-scale SSF with frass resulted in high proteases activity (65 U g-1), which increased 52% when BSG was mixed with frass (1:1, w/w). The optimal conditions from Box-Behnken design using frass:BSG mixture resulted in 152 U g-1 of proteases activity, which is in full accordance with the value predicted by the model. SSF scale-up with 50 g of frass:BSG increased proteases activity up to 202.2 U g-1. This study presents an innovative utilization of insects’ by-products in the field of enzymes production in full accordance with the circular economy guidelines.