Celulases de origem fúngica e endógena em insetos aquáticos fragmentadores

Abstract

Insects have different feeding strategies and one of them is the use of lignocellulosic substrates as an energy source, which makes these organisms an ideal source for prospecting for new cellulolytic enzymes. The organic matter used as a food resource is usually colonized by microorganisms. These convert the plant substrate to a palatable nutritional state, through the production of enzymes that degrade this polymer. The search for new sources of cellulolytic enzyme production has brought increasing evidence that cellulases are present in the animal kingdom, particularly in insects. Thus, this study aimed to identify the diversity of cultivable filamentous fungi associated with the digestive tract of larvae of three shredder aquatic insects, to qualitatively and quantitatively evaluate the production of cellulolytic enzymes from cultivable filamentous fungi associated with the digestive tract of fragmenting aquatic insect larvae, describe the profile of gene expression of cellulases of the digestive tract of larvae of Phylloicus amazonas (Insecta: Trichoptera). Larvae from three aquatic insect genera: Phylloicus (Trichoptera), Triplectides (Trichoptera) and Stenochironomus (Diptera) were studied. A total of 28 morphospecies associated with the intestine of these insect larvae were identified, comprising Aspergillus, Cladosporium, Paecilomyces, Penicillium, Pestalotiopsis and Trichoderma. Regarding the qualitative evaluation of cellulolytic enzyme production, 176 isolates produced a hydrolysis halo. The results of the enzymatic analysis, carried out through the quantification of reducing sugars, showed that the fungus Penicillium sp. A2PA4 has a good capacity for cellulose degradation. Through gut transcriptome analysis of Phylloicus amazonas Pather, 2003 larvae it was possible to find the signature of Endoglucanase and β-glucosidase genes. The results obtained indicate that the gut of aquatic insect larvae is a substrate with potential for both bioprospecting fungi producing cellulolytic enzymes and endogenous cellulase genes.