Isolation and characterization of cellulolytic microorganisms from the Oncideres albomarginata chamela hindgut

Lignocellulosic biomass is an important food source for xylophagous insects. The ability to degrade lignocellulosic mass gives to these insects an important position in the transformation of biomass to simpler compounds. This degradation process is possible due to a dual digestion system conformed by the enzymes (cellulases and hemicellulases) of the insect itself and the enzymes of the microorganisms that are in a symbiotic relation with the insect. However, the contribution of each microorganism in this process is not clear enough. The intestinal tract of xylophagous insects is highly differentiated into foregut, midgut and hindgut, of which, hindgut represents an important reservoir of bacteria and fungi with a biotechnological potential in the enzyme and biofuel production. In this study, we evaluated the presence of cellulolytic microorganisms in the hindgut of the stem-borer Oncideres albomarginata chamela and the enzymatic activity of cellulases of the isolated microorganisms. Our results indicated that there are cultivable microorganisms in the hindgut of O. albomarginata chamela. These microorganisms were isolated from a culture medium rich in CMC (Carboxymethyl-cellulose) and then they were identified by molecular methods using universal markers. Ten different microbial isolates were identified, and among these, we found two fungus (Penicillium sp. and Phaeosphaeria sp.) and two bacteria (Pseudoarthrobacter spp.) species with an interesting cellulase enzymatic activity evaluated by diffusion on plate assays and by the DNS (3, 5 Dinitrosalicylic acid) method. These results confirm that insect guts represent a valuable source of novel cellulolytic microorganisms and enzymes useful for cellulose degradation.