Identification and characterization of novel cellulolytic activity from salivary and digestive fluids of Dissosteira carolina (Orthoptera: Acrididae)

The main goal of our project is to identify novel insect cellulases with potential for use as enzyme catalysts for biotechnological processing of plant biomass into biofuel. Screening of salivary and gut fluids from insect species belonging to five insect Orders using carboxymethylcellulose (CMC) and microcrystalline cellulose (MCC) as substrates demonstrated relatively high cellulolytic activity in fluids from the Carolina grasshopper (Dissosteira carolina). Using zymography, we detected four distinct cellulolytic bands in gut fluids from this insect and established their expression in different instars and gut regions. Size exclusion and anion exchange chromatography were used to purify these cellulases from D. carolina gut fluid mixtures. Results from our work demonstrate the presence of novel cellulases in the digestive system of D. carolina. Considering that these grasshoppers feed on diverse grassy plant material, and the proposed use of switchgrass as feedstock for bioethanol production, characterization of these novel cellulolytic enzymes would allow for their potential application in plant biomass biodegradation for biofuel production.