Endophytic fungi are considered a rich source of active compounds resulting from their secondary metabolism. Fungi from marine environment grow in a habitat with unique conditions that can contribute to the activation of metabolic pathways of synthesis of different unknown molecules. The production of these compounds may support the adaptation and survival of the fungi in the marine ecosystem. Mangroves are ecosystems situated between land and sea. They are frequently found in tropical and subtropical areas and enclose approximately 18.1 million hectares of the planet. The great biodiversity found in these ecosystems shows the importance of researching them, including studies regarding new compounds derived from the endophytic fungi that inhabit these ecosystems. 3-hydroxypropionic acid (3-HPA) has been isolated from the mangrove endophytic fungus Diaporthe phaseolorum, which was obtained from branches of Laguncularia racemosa. The structure of this compound was elucidated by spectroscopic methods, mainly 1D and 2D NMR. In bioassays, 3-HPA showed antimicrobial activities against both Staphylococcus aureus and Salmonella typhi. The structure of this antibiotic was modified by the chemical reaction of Fischer-Speier esterification to evaluate the biologic activity of its chemical analog. The esterified product, 3-hydroxypropanoic ethyl ester, did not exhibit antibiotic activity, suggesting that the free carboxylic acid group is important to the pharmacological activity. The antibiotic-producing strain was identified with internal transcribed spacer sequence data. To the best of our knowledge, this is the first report of antibacterial activity by 3-HPA against the growth of medically important pathogens.

The genus Leuconostoc belongs to a group of lactic acid bacteria usually isolated from fermented vegetables, which includes species involved in the production of exopolysaccharides (EPS). These biopolymers possess considerable commercial potential. Because of the wide variety of industrial applications of EPS, this study aimed to produce and characterize the native exopolysaccharide strain Leuconostoc pseudomesenteroides R2, which was isolated from cabbage collected in a semi-arid region of Bahia. We employed the following conditions for the production of EPS: 10.7% sucrose, pH 8.2, without agitation and incubation at 28°C for 30 hours. The fermentation broth was treated with ethanol and generated two types of polysaccharide substances (EPS I and EPS II). The identification of EPS I and EPS II was conducted using FT-IR, 1 H, 13 C and DEPT-135 NMR spectra. The two substances were identified as linear dextran α polysaccharides (1 → 6) which indicated different characteristics with respect to thermal analysis and density of free packaging, viscosity and time of solubilization. Both dextrans are of low density, possess high thermal stability and exhibited the behavior characteristic of pseudoplastic polymers.

The chemical reactions carried out by microorganisms have been used as a tool in modern chemistry. This paper reports the production of mycophenolic acid and a new phthalide by the endophytic fungus Penicillium crustosum obtained from coffee seeds. The fungus was cultivated in a liquid medium for a period of seven days and after that the culture medium was divided into four treatments: A, B, C and D, to which different organic substances were added. Treatment A was maintained as the control to evaluate the occurrence of biotransformation. Organic acids were added to the culture media of treatments B (ferulic and quinic acids) and C [cinnamic and 3,4-(methylenedioxy) cinnamic acids], and caffeine was added in the treatment D. All these organic compounds were dissolved in DMSO, and the fermentation was maintained for more 13 days, totalizing 20 days. Mycophenolic acid was isolated from the culture with no added acids (treatment A). Mycophenolic acid and a new phthalide, 5-hydroxy-7-methoxy-4-methylphthalide were isolated from treatments B and C, and mycophenolic acid and caffeine (added to the culture medium) were isolated from treatment D. The structures were determined by NMR techniques and confirmed by MS and MS/MS techniques.

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