Beneficial interactions between plants and microorganisms have been investigated under different ecological, physiological, biochemical, and genetic aspects. However, the systematic exploration of biomolecules with potential for biotechnological products from this interaction still is relatively scarce. Therefore, this study aimed the evaluation of the diversity and antimicrobial activity of the endophytic fungi obtained from roots, stems and leafs of Myrcia guianensis (Myrtaceae) from the Brazilian Amazon. 156 endophytic fungi were isolated and above 80% were identified by morphological examination as belonging to the genera Pestalotiopsis, Phomopsis, Aspergillus, Xylaria, Nectria, Penicillium and Fusarium. Fermented broth of those fungi were assayed for antimicrobial activity and four inhibited the growth of Staphylococcus aureus, Enterococcus faecalis, Candida albicans and Penicillium avellaneum. As the strain named MgRe2.2.3B (Nectria haematococca) had shown the most promising results against those pathogenic strains, its fermented broth was fractioned and only its two low polar fractions demonstrated to be active. Both fractions exhibited a minimum bactericidal concentration of 50 μg.mL(-1) against S. aureus and a minimum fungicidal concentration of 100 μg.mL(-1) against P. avellaneum. These results demonstrate the diversity of fungal genera in M. guianensis and the potential of these endophytic fungi for the production of new antibiotics.

A water quality index has not been developed for Amazonian blackwater rivers. In this paper, we used data collected in recent years to address this gap. An index was constructed using, in total, 342,930 analyses involving 161 water quality parameters. All analyses were part of ten large-scale campaigns, which took place between 2021 and 2023. The modifications proposed by the adoption of the new WQI enabled changes in the water quality results of the Amazon region, in comparison with an index used in other parts of Brazil. The proposal is a long-awaited tool that can significantly assist in the next stage in the preservation of this vast national wealth, which is the Amazon basin.

Fungal biotransformation is a pertinent strategy to overcome difficulties and problems arising from chemical synthesis and direct extraction from nature. This biotechnological approach is a relevant strategy to obtain high-added-value aroma compounds under environmentally friendly conditions. In order to understand the effect of an amazon endophytic fungus on the monoterpene substrate, this research work aims to investigate the biotransformation using cells cultivated of Pestalotiopsis versicolor LabMicrA-478 with R-(+)-limonene as a sole carbon and energy source. The main products of the limonene biotransformation identified by gas chromatography-mass spectrometry (Thermo Scientific™) with the NIST database were limonene-1,2-diol (74,97%) and limonene-1,2-epoxide (1.94%) in 120 hours of reaction. Finally, this is the first report to characterize the bioconversion of R-(+)-limonene by P. versicolor LabMicrA-478, as a biocatalyst.

Indicator bacteria, such as thermotolerant and fecal coliforms, particularly Escherichia coli, are employed as markers of water pollution, and their presence in water sources is attributed to human fecal contamination. The Puraquequara Basin in Manaus, AM, serves as case study due to its exposure to diverse anthropogenic activities. Its contaminants include microbial pollutants such as thermotolerant coliforms, fecal coliforms and other pathogenic bacteria. Predictive models for water quality monitoring provide an effective means of identifying microbiological hazards and assessing potential health risks. This study aims to develop a predictive statistical model for estimating thermotolerant coliform and Escherichia coli concentrations based on physicochemical water parameters in the Puraquequara Basin. The study was conducted over a 10-month period, from August 2022 to June 2023. A total of 68 samplings were performed, during which 20 physicochemical and microbiological water quality parameters were analyzed. The physicochemical and biological parameters were analyzed following the standardized methodologies recommended by the Standard Methods for the Examination of Water and Wastewater. A Multiple Linear Regression (MLR) model was developed to assess the influence of physicochemical parameters on E. coli and total coliform contamination in the Puraquequara Basin. The evaluated parameters suggest that the Puraquequara basin is undergoing a contamination process, making this natural environment conducive to microorganism development. The concentration graphs for coliforms and E. coli display human activities that occur more frequently, such as during the drier months when visitation increases, which elevates microbiological contaminant levels at the sampling points closest to these areas. The MLR analysis was statistically significant, although it demonstrated limited explanatory power for both total coliform (R² = 0.178, p <0.05) and I (R² = 0.220, p <0.05) analyses. Selected parameters for total coliform were statistically significant.