Fungos filamentosos associados ao trato intestinal de insetos detritívoros: uma avaliação do potencial enzimático biotecnológico

Abstract

Fungi are versatile organisms, decomposers of organic matter and capable of transforming substances into useful nutrients for animals and plants. The study of enzymes draws the attention of researchers for their potential application in plant material rich in starch, cellulose, lignocellulose that can be used as sources for biofuel production. In addition, fungi are microorganisms that produce antioxidant metabolites useful in preventing undesirable physiological effects. The objective was to identify fungi associated with the insect digestive tract and to evaluate the amylolytic potential of fungi as a possible source of biotechnological applications. The filamentous fungal strains were inoculated in mineral solution for enzyme extract production. The enzyme extract of each strain was analyzed in a colorimetric test to select the best strains producing enzymes of interest. Four strains were selected and identified by genetical sequencing: Endomelanconiopsis endophytica (CRC T2PB10), Myxospora musae (CRC T5PC4), Neopestalotiopsis cubana (CRC T6PC1) e Fusarium pseudocircinatum (CRC T6PA6). The strains CRC T2PB10, CRC T6PC1 e CRC T6PA6 were submitted to assays for specific enzymatic activity by colorimetric method, characterization of optimal temperature and pH, and quantification of bioethanol in gas chromatographic assay. Enzyme extract of each isolate was applied on sweet potato starch for simultaneous saccharification and fermentation for bioethanol production. 17.3 - 88.1 % bioethanol was produced in relation to the theoretical expected yield. Additionally, antioxidant activity, chemical group analysis, and morphology assays were performed on the strains CRC T2PB10, CRC T5PC4, CRC T6PC1 e CRC T6PA6. Morphology was performed by optical microscopy stained with Toluidine Blue and measurement performed using the ImageJ software. . Antioxidant activity performed in TLC and by quantitative method for DPPH and hydrogen peroxide (H2O2) radicals. The TLC showed several spots with acetone/chloroform mobile phase and UV 254 nm developers and I2 vapor. Fungal extracts demonstrate antioxidant action to reduce the DPPH free radical and especially for H2O2 above 50%, repectively, CRC T2PB10 – 91.6%, CRC T5PC4 – 87.8%, CRC T6PC1 – 89.5% and 92.3% for CRC T6PA6. This study demonstrated that the fungi showed efficient ethanol production and chemical compounds with antioxidant activity. Thus, work, should be carried out evaluating these four species for industrial use.