Nanopartículas metálicas biossintetizadas por fungos endofíticos isolados de amêndoas de Bertholletia excelsa ducke

Abstract

INTRODUCTION: The search for biological methods to obtain metallic nanoparticles is highlighted due to the diverse biotechnological applications, these procedures appear as alternative to traditional, physical and chemical methods. OBJECTIVE: Biosynthesis of silver metallic nanoparticles (AgNP) and copper (CuNP) by endophytic fungi isolated from Bertholletia excelsa (Brazil nut) almonds from Amazonia. METHODOLOGY: An initial screening with six endophytic fungi was carried out: Aspergillus sp. (Biorg 5), Trichoderma sp. (Biorg 7), Phaeoacremonium sp. (Biorg 15), Rhizopus sp. (Biorg 16), Aspergillus sp. (Biorg 22) and Clamidosporium sp. (Biorg 36), an experimental design was used to obtain the best AgNps biosynthesis conditions for the fungus that produced Nps in smaller size. For the CuNPs, different co-substrates were used: NpBP, NpEtOH, NpGly and NpAsc, followed by infrared characterization with fourier transform, besides evaluating the effects of copper on the growth and morphology of Phaeoacremonium sp. RESULTS AND DISCUSSION: after screening with endophytic fungi, Phaeoacremonium sp. (Biorg 15) produced AgNPs up to 44.06 nm in size. The characterization of AgNPs by FTIR suggests interactions between the phosphate cofactor and mycelial components of the fungus Phaeoacremonium sp. with AgNPs. The silver NPs showed antibacterial activity against the strains Staphylococcus aureus (ATCC33591), Staphylococcus epidermidis (ATCC12228), Proteus mirabilis (ATCC 15290) and Klebsiella pneumoniae (ATCC 4352) and the ecotoxicity tests on microalgae Chlorella vulgaris showed high toxicity in concentrations (10 mmol and 0.001 mmol). Regarding the CuNPs, the results showed that the co-adjuvant phosphate produced CuNPs of 66.84 dm with -34 mV zeta potential. The FTIR analysis corroborates the formation of CuNPs. In the case of growth analysis of halo in solid medium in the presence of the metal, there was slight deformation in the growth of Phaeoacremonium sp. While in the absence of the metal, no morphological effect was observed.CONCLUSIONS: The endophytic fungi isolated from Bertholletia excelsa were able to produce AgNPs at CuNPs in sizes ranging from 50-300 nm as a viable alternative, low cost, no addition of toxic agents and mild conditions, and demonstrate potential biocides against bacteria and toxicity in microalgae C. vulgaris. While to obtain the CuNPs the reducing agents played the role of cappers and protectors