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Kefir, a combined consortium of bacteria and yeast encapsulated by a polymeric matrix of exopolysaccharides, was used as anodic biocatalyst in a two-chamber microbial fuel cell (MFC). Fermentation was followed during 72 h and polarization curves were obtained from linear sweep voltammetry. The effect of methylene blue as charge-transfer mediator in the kefir metabolism was evaluated. UV/Vis spectrophotometry and cyclic voltammetry were applied to evaluate the redox state of the mediator and to characterize the electrochemical activity, whereas current interruption was used for internal resistance determination. Aiming to establish a relationship between the microbial development inside the anodic chamber with the generated power in the MFC, total titratable acidity, pH, viscosity, carbohydrate assimilation, and microbial counting were assayed. The kefir-based MFC demonstrated a maximum power density of 54 mW m−2 after 24 h fermentation, revealing the potential use of kefir as a biocatalyst for microbial fuel cells.

Kefir is a fermented beverage originating form the Caucasian regions composed of a number of bacteria and yeasts living together in polysaccharide grains secreted by them. Kefir can be considered a probiotic source as it presents anti-bacterial, anti-mycotic, anti-neoplasic and immunomodulatory properties. Aiming to appraise a possible anti-inflammatory effect of kefir we conducted cotton-induced granuloma and paw oedema assays in rats, the latter using carrageenan, dextran and histamine as stimuli. Kefir samples were thawed and continuously cultured during 15 days both in a molasses solution (50 g/l) and in cow's milk. A polysaccharide extract isolated from the grains (kefiran) was also tested in cotton-pellet experiments. The results showed significant inhibition in the formation of granuloma tissue for all the test groups, as compared to the blank group. Kefir suspensions in molasses presented an inhibition of 41 +/- 3% for the inflammatory process, fermented milk prepared from kefir showed 44 +/- 6% inhibition and kefiran extract 34 +/- 15%. Rat paw oedema also showed significant decreases with the mediators. Dextran-induced oedema was completely inhibited at 1 h after input, with a 76% inhibition after 2 h. Carrageenan stimulus was inhibited 62% after the 3rd hour, and histamine by 52% after the 2nd hour. These results points to the existence of anti-inflammatory prebiotic compounds present in symbiotic cultures of kefir growing in both aqueous and milky suspensions.

The ozonised sunflower oil, Bioperoxoil®, was tested for its antimicrobial activity against some pathological strains in vitro together with its healing potential against Staphylococcus aureus in vivo. Bioperoxoil® was tested against S. aureus, Pseudomonas aeroginosa, Candida albicans, S. typhimurium and Escherichia coli suspensions using the agar diffusion method. Healing experiments were carried out with Wistar rats through topical application of 3.5 mg/ml of the ozonised oil up to the 7th day after inoculation with S. aureus. Bioperoxoil® showed anti-inflammatory effects against all strains tested, with MIC values ranging from 2.0 to 3.5 mg/ml. Bioperoxoil® also demonstrated protective effects on skin connective tissue and to enhance wound healing during the treatment, as compared to a neomycin–clostebol association used as a positive control. The overall results indicated a significant antimicrobial activity, anti-inflammatory and wound-healing properties for Bioperoxoil®, as compared to other antimicrobial agents commercially available.

O cogumelo tibetano (CT) é uma bebida probiótica fermentada por um grande conjunto de bactérias e leveduras, algumas das quais de conhecida atividade antimicrobiana, imunomodulatória, pró-digestiva e auxiliar da peristalse intestinal. Neste sentido, este trabalho teve como objetivo avaliar a possível ação da suspensão produzida pelo CT sobre a motilidade intestinal de ratos. Foram utilizados grupos de animais (ratos Wistar albinos machos, n = 6/grupo) pesando 200 ± 20 g. Os diferentes grupos foram tratados v.o. durante 15 dias (1,5 mL/animal de fermentado de 24 h de CT em cultivo contínuo em 50 g/l de açúcar mascavo comercial em água destilada), e os demais grupos tratados com água destilada (1,5 mL/animal). Após 15 dias os animais foram mantidos em jejum por 24 hs, e tratados com suspensão de CT (1,5 mL/animal/v.o), água destilada (controle, 1,5mL/animal/v.o), acetilcolina (1mg/kg/s.c.) e atropina (1mg/kg/i.m.). Após 30 min, os animais receberam uma suspensão de carvão ativo 10 % (0,1 mL/10 g, v.o), seguindo-se eutanásia após 45 min, excisão da porção do piloro até o início do ceco, e determinação da distância percorrida pelo carvão. A administração da suspensão de CT aumentou o trânsito intestinal em 68,7 % e os demais tratamentos apresentaram as seguintes percentagens: atropina 20,2 %, acetilcolina 78,7 % e controle 42,9 % (p < 0,05, ANOVA seguido de teste de Tukey-Kramer). Esses resultados mostraram que a suspensão de CT estimulou o peristaltismo nos animais, o que sugere um efeito positivo na digestão e absorção alimentar para o consórcio microbiano. The Tibetan mushroom (CT) is a probiotic beverage fermented by a big group of bacteria and yeasts, some of which of well-known anti-bacterial activity, immunomodulatory, pro-digestive and to aid of the intestinal peristalsis. In this sense, this work had the aim of evaluating the possible action of the suspension produced by CT on the peristalsis intestinal of rats. Animal groups weighing 200 ± 20 g were used (Wistar rats (male, n = 6/group)). The different groups were treated v.o. for 15 days (1,5 mL/animal of 24h fermented of CT in continuously cultured into molasses solutions (50 g/l)), and the other groups treated with distilled water (1,5 mL/animal). After 15 days the animals were maintained in fast for 24h, and treated with suspension CT (1,5 mL/animal/v.o), distilled water (control, 1,5mL/animal/v.o), acetylcholine (1mg/kg/s.c) and atropine (1mg/kg/i.m). After 30 min, the animals received a suspension of active coal 10% (0,1 mL/10g, v.o), after the euthanasia, excision of the portion of the pylorus to the beginning of the cecum, and determination of the distance traveled by the coal. The administration of the CT suspension increased the intestinal peristalsis in 68,7% and the other treatments presented the following percentages: atropine 20,2%, acetylcholine 78,7% and control 42,9% (p < 0,05, ANOVA followed by Tukey-Kramer test). Those results showed that the CT suspension stimulated the peristalsis in the animals, what suggests a positive effect in the digestion and alimentary absorption for the microbial consortium.