Selenium is an essential micronutrient for living beings, as it helps to maintain the normal physiological functions of the organism. The numerous discoveries involving the importance of this element to the health of human beings have fostered interest in research to develop enriched and functional foods. The present study evaluated the potential for bacterial strains of Enterococcus faecalis (CH121 and CH124), Lactobacillus parabuchneri (ML4), Lactobacillus paracasei (ML13, ML33, CH135, and CH139), and Lactobacillus plantarum (CH131) to bioaccumulate Se in their biomass by adding different concentrations of sodium selenite (30 to 200 mg/L) to the culture medium. Quantification of Se with UV and visible molecular absorption spectroscopy showed that the investigated bacteria were able to bioaccumulate this micromineral into their biomass. Two of the L. paracasei strains (ML13 and CH135) bioaccumulated the highest Se concentrations (38.1 ± 1.7 mg/g and 40.7 ± 1.1 mg/g, respectively) after culture in the presence of 150 mg/L of Se. This bioaccumulation potential has applications in the development of dairy products and may be an alternative Se source in the diets of humans and other animals.

Cephalexin (CEX) is an antibiotic commonly used to treat bacterial infections in humans and animals. However, it can be considered a micropollutant. Thus, this study evaluated the degradation of CEX using ultraviolet irradiation (UV-C) and analyzed the by-products as well as their residual antimicrobial activity. A reactor with a mercury vapor lamp was used for the degradation. Irradiated CEX solution were collected over a period of 4 h and analyzed by High Performance Liquid Chromatography coupled with Mass Spectrometry. For the residual antimicrobial activity the susceptibility test was performed by broth microdilution against Staphylococcus aureus and Escherichia coli microorganisms. It was found that CEX, after treatment, generated a metabolite with a mass of 150 m/z in 15 min, and a 4- and 8-fold increase in the minimum inhibitory concentration of the drug against S. aureus and E. coli, could be observed, respectively, after 20 min. Therefore, this treatment proved to be effective in the degradation of CEX, being able to degrade 81% of the initial molecule of the drug in 20 min. Furthermore, the antimicrobial activity of the CEX solution decreased as the irradiation time increased, indicating loss of antimicrobial function of the initial CEX molecule and the resulting by-products.

This study aims to verify the most suitable substrate formulation based on proportions of earthworm humus and soil to improve the quality of organic strawberries. Vermicomposting generated humus and strawberry seedlings were planted in different humus:soil ratios: (0:100; 20:80; 40:60; 60:40; 80:20 and 100:0, respectively). The proportional conditions were characterized after planting and after 60-day cultivation, plants were harvested, and chemical characterizations of the soil and plants were made. We verified that with an increase of humus content in the substrate, an increase in values of N, P, K, pH and organic matter in soil and dry and fresh mass in shoot area of the plants were noticed. In relation to fruits, pH, humidity and sodium concentration, the authors noticed no change under any conditions and ash content was lower when an increase of humus in soil was observed. Higher values of potassium and protein occurred from 40:60 and 60:40, respectively. Higher values for average strawberry production were verified from 60:40 condition. Reducing sugars and titratable acidity increased and stabilized at 20:80 and 60:40, respectively. Thus, in order to avoid excess of nutrients in the substrate, which can hinder plant growth, humus condition in the ratio 60:40 humus:soil is recommended for higher values of production, nutrients and protein in strawberry cultivation.

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É de grande preocupação o estado em que se encontra o meio ambiente com relação à poluição. Uma nova classe de poluentes está chamando a atenção dos pesquisadores e órgãos governamentais, chamadas de micropoluentes emergentes, preocupantes por serem substâncias tóxicas capazes de gerar danos ao meio ambiente mesmo em pequenas quantidades. Uma das classes de micropoluentes são os fármacos, entre eles, estão os antibióticos, consumidos tanto por medicina humana como medicina veterinária. Para a indicação da presença de alteração ambiental, podem ser usados organismos vivos, chamados de bioindicadores ou indicadores biológicos. As minhocas são consideradas bioindicadores da qualidade do solo realizando também o processo de vermicompostagem, usado para a degradação da matéria orgânica. Assim, o objetivo do trabalho foi avaliar o efeito do antibiótico cefalexina em processo de vermicompostagem, utilizando minhocas da espécie Eisenia andrei. Foram feitos minhocários em pequena escala, com solo contendo o antibiótico, nas concentrações de 250 mg/kg, 500 mg/kg e 1000 mg/kg, monitorados por um período de 4 meses. Os parâmetros analisados no solo foram sódio, potássio, nitrogênio e pH do húmus gerado pelo processo de vermicompostagem. Já para as minhocas avaliou-se a biomassa, reprodução, fuga e mortalidade. Como resultado, foi possível observar que não houve alteração nos parâmetros analisados. Conclui-se que o antibiótico cefalexina, nas concentrações testadas, não alterou a reprodução e biomassa das minhocas, bem como a qualidade de húmus gerado.