Pleurotus ostreatus fungus forms an edible mushroom that possesses important nutritional and medicinal properties. Selenium (Se) is essential to human diets and it is in low concentration in the soil, and consequently in food. P. ostreatus was grown in coffee husks enriched with various concentrations of sodium selenite. The biological efficiency of P. ostreatus was affected by the addition of high concentrations of Se. The highest level of Se absorption was obtained by adding 51 mg kg 1 of sodium selenite. The mushrooms from first flush contained more Se than the further flushes. These results demonstrate the great potential of coffee husks in the production of Se-enriched mushrooms and show the ability of this fungus to absorb and biomagnify Se.

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Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

To initiate a conservation program of the Orchidaceae from the Brazilian Atlantic rain forest with the purpose of ex situ conservation or reintroduction in the State of Minas Gerais, seven mycorrhizal Rhizoctonia-like fungal strains were isolated from roots of seven neotropical orchid species from three different Atlantic rain forest fragments. Taxonomic studies revealed that the isolates belong to the genera Ceratorhiza and Epulorhiza. The Epulorhiza isolates were identified as Epulorhiza repens (N. Bernard) R.T. Moore and Epulorhiza epiphytica Pereira, Rollemberg et Kasuya. RAPD analysis indicated higher polymorphism between Epulorhiza epiphytica and Epulorhiza repens than found in the PCR-RFLP analysis. RAPD and morphological analyses indicated a degree of relatedness among the Ceratorhiza isolates obtained from the roots of different Oncidium species. A combination of morphological and molecular characterizations permitted integration of fungal strain identification with genetic relatedness among the isolates, thus allowing some inferences to be made on specificity of these endosymbionts under field conditions. Résumé : Les auteurs travaillent à mettre sur pied un programme de conservation pour les Orchidaceae de la forêt ombrophile atlantique du Brésil, avec l'objectif d'effectuer de la conservation ex situ et de la réintroduction, dans l'état de Minas Gerais. À cette fin, ils ont isolé sept souches de champignons de type Rhizoctonia, à partir de racines de sept espèces d'orchidées néotropicales, provenant de trois fragments différents de la forêt ombrophile de l'Atlantique. Les études taxonomiques révèlent que les isolats appartiennent aux genres Ceratorhiza et Epulorhiza. Ils ont identifié les isolats d'Epulorhiza comme Epulorhiza repens (N. Bernard) R.T. Moore et Epulorhiza epiphytica Pereira, Rollemberg et Kasuya. L'analyse RAPD montre un polymorphisme plus grand entre l'Epulorhiza epiphytica et l'Epulorhiza repens, que celui qu'on retrouve avec les analyses PCR-RFLP. Les analyses RAPD et morphologiques indiquent un certain degré de relation entre les isolats provenant des Ceratorhiza obtenus des racines de différentes espèces d'Oncidium. La combinaison des caractéristiques morphologiques et moléculaires permet d'intégrer l'identification des souches fongiques avec la relation génétique entre les isolats, permettant ainsi de déduire des informations sur la spécificité de ces endosymbiontes, sous des conditions de terrain.

The capability of Pleurotus ostreatus mushroom to accumulate lithium (Li) and the accessibility of this Li compared with lithium carbonate (Li(2)CO(3)), often used as psychiatric medicine, were investigated. Mushrooms were produced on a substrate-based on coffee husk, with different added concentrations of lithium chloride (LiCl). Biological efficiency (BE), the crude protein content, the concentration of Li and other elements present in mushrooms were determined. The sequential extraction and in vitro test were used to verify the accessibility and the degree of solubility of this element. Li concentration in mushrooms was directly influenced by increasing LiCl concentration in the substrate (P<0.05). The BE was not affected by different concentrations of LiCl. Li present in enriched mushrooms showed greater accessibility than in Li(2)CO(3). Therefore, P. ostreatus mushrooms, enriched with lithium can be an alternative source of Li, as well as being a food with high nutritional value.