Exploration of Protease Resources in the Gut of Omnivorous (Orthoptera: Gryllotalpidae).

An insect's gut microbiome is an essential "organ" in their life cycle, playing a crucial role by aiding food digestion and nutrient absorption. This study employed both culture-independent and culture-dependent methods to explore the protease resources present in the gut of the omnivorous insect . The findings revealed that the gut extract of contained a diverse array of proteases, including cysteine proteases, pepsin, serine proteases, and trypsin, as well as some unidentified proteases. Furthermore, the protease gene , derived from gut bacterium DX-3, has been cloned and recombinantly expressed. The recombinant DX-3- protease exhibited a 61.9-fold increase in fermentation level compared to the DX-3 protease. This protease was characterized as a neutral, heat-resistant metalloprotease with an M48 peptidase domain, and it was observed that the binding of Ca to the recombinant protease resulted in the formation of the largest active pocket. This study provides technical support for further development and utilization of functional protein resources in insect gut.