Bioactive compounds, e.g., protein, polyunsaturated fatty acids, carotenoids, vitamins and minerals, found in commercial form of microalgal biomass (e.g., powder, flour, liquid, oil, tablet, or capsule forms) may play important roles in functional food (e.g., dairy products, desserts, pastas, oil-derivatives, or supplements) or feed (for cattle, poultry, shellfish, and fish) with favorable outcomes upon human health, including antioxidant, anti-inflammatory, antimicrobial, and antiviral effects, as well as prevention of gastric ulcers, constipation, anemia, diabetes, and hypertension. However, scale up remains a major challenge before commercial competitiveness is attained. Notwithstanding the odds, a few companies have already overcome market constraints, and are successfully selling extracts of microalgae as colorant, or supplement for food and feed industries. Strong scientific evidence of probiotic roles of microalgae in humans is still lacking, while scarce studies have concluded on probiotic activity in marine animals upon ingestion. Limitations in culture harvesting and shelf life extension have indeed constrained commercial viability. There are, however, scattered pieces of evidence that microalgae play prebiotic roles, owing to their richness in oligosaccharides—hardly fermented by other members of the intestinal microbiota, or digested throughout the gastrointestinal tract of humans/animals for that matter. However, consistent applications exist only in the dairy industry and aquaculture. Despite the underlying potential in formulation of functional food/feed, extensive research and development efforts are still required before microalgae at large become a commercial reality in food and feed formulation.

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We tested the effects of desiccation and type of sediment (clay or sand) on the regeneration of fragments of the apical shoots of three species of Hydrocharitaceae: Egeria najas, E. densa and Hydrilla verticillata. The shoots were left to dry on clay or sand from zero to four days, and were then returned to aquaria containing water. To approximate natural conditions, the aquaria containing clay had higher turbidity and nutrient (P and N) concentrations than did the aquaria with sand. All species dried faster on sand substrate, which led to lower regeneration (in terms of dry weight, length, sprout and root formation) in this treatment. H. verticillata fragments elongated faster than the other species, but E. najas was the most successful species (in terms of increase in dry weight) in the sand treatment. Our results indicate that the exotic H. verticillata has a competitive advantage, at least in its early stages of regeneration, over the other two, native species, especially in more eutrophic and turbid habitats; whereas E. najas fragments have a competitive advantage in less-turbid, oligotrophic and sand-dominated sites.

ABSTRACT. This work suggests the study of the coagulation diagram as a tool to verify the efficiency in removing color and turbidity of the water, using the Moringa oleifera Lam and the association of this biopolymer with the aluminium sulphate as coagulating agents. The assays were carried out in Jar Test, by varying the concentrations of coagulants and pH of coagulation. After the assays of coagulation/flocculation/sedimentation, samples were collected for the evaluation of the process efficiency. Best results were obtained at dose of 50 ppm of Moringa oleifera Lam. When associating the coagulants, the addition of the aluminium sulphate provided an increase in the efficiency of coagulation/flocculation, whose parameters of control used were color and turbidity. It was verified that the study of the coagulation diagram is useful, since it enables developing the assays in the optimal range, as a function of the raw water characteristics. The use of the Moringa oleifera Lam can be considered as an alternative technique to the conventional treatment.Keywords: water treatment, biopolymer, chemical coagulant, quality parameters.Diagramas de coagulação utilizando a Moringa oleifera Lam e o sulfato de alumínio, visando a remoção de cor e turbidez da água RESUMO. Este trabalho propõe o estudo dos diagramas de coagulação como ferramenta para verificar a eficiência de remoção de cor e turbidez da água bruta, utilizando como coagulante a Moringa oleifera Lam e a associação deste biopolímero com o sulfato de alumínio. Os ensaios foram realizados em Jar Test, variandose as concentrações dos coagulantes e o pH de coagulação. Após os ensaios de coagulação/ floculação/sedimentação, foram coletadas amostras para a avaliação da eficiência do processo. Os melhores resultados obtidos para os parâmetros avaliados corresponderam a uma dosagem de solução padrão de Moringa oleifera Lam equivalente a 50 ppm. Quando da associação dos coagulantes, a adição do sulfato de alumínio proporcionou um aumento na eficiência da coagulação/floculação, cujos parâmetros de controle utilizados foram cor e turbidez. Verificou-se que o estudo do diagrama de coagulação é útil, pois possibilita o desenvolvimento dos ensaios nas regiões ótimas, em função das características da água bruta. A utilização da Moringa oleifera Lam pode ser considerada como uma técnica alternativa ao tratamento convencional.Palavras-chave: tratamento de água, biopolímero, coagulante químico, parâmetros de qualidade.

This study aimed to evaluate the efficiency of the coagulation/flocculation/dissolved air flotation (C/F/DAF) process using the coagulant Moringa oleifera (MO) seed powder, and to analyse the profile of fatty acids present in the generated sludge after treatment. For the tests, deionized water artificially contaminated with cell cultures of Anabaena flos-aquae was used, with a cell density in the order of 10(4) cells mL(-1). C/F/DAF tests were conducted using 'Flotest' equipment. For fatty acid profile analyses, a gas chromatograph equipped with a flame ionization detector was used. It was seen that the optimal dosage (100 mg L(-1)) of MO used in the C/F/DAF process was efficient at removing nearly all A. flos-aquae cells (96.4%). The sludge obtained after treatment contained oleic acid (61.7%) and palmitic acid (10.8%). Thus, a water treatment process using C/F/DAF linked to integral MO powder seed was found to be efficient in removing cells of cyanobacteria, and produced a sludge rich in oleic acid that is a precursor favourable for obtaining quality biodiesel, thus becoming an alternative application for the recycling of such biomass.

The objective of this study is to investigate the impacts of anionic polymer as a flocculant aid on the coagulation/flocculation performance with a saline solution of Moringa oleifera as a coagulant to provide larger flocs and decrease the time sedimentation. For the tests, raw water was used from Pirapó River Basin (Maringá, Paraná, Brazil). Optimization of coagulation/flocculation tests was initially performed in a jar-test with a dosage of M. oleifera Lam (crude extract--MO, oil-extracted with ethanol--MO (et) and hexane--MO (hex) 1% m/v) as the coagulant that ranged from 10 to 60 mg L(-1) and of the anionic polymer 0.1% as a flocculant aid with a dosage that ranged from 0 to 0.4 mg L(-1). The parameters analysed were colour, turbidity and compounds with absorption in UV254nm. In view of the statistical analysis results, MO (hex) with a dosage of 30 mg L(-1) was chosen as a coagulant for the next tests of coagulation/flocculation. When anionic polymer was used alone (0.0 mg L(-1) of MO (hex)), parameters were not removed and there was no generation of heavy flocs as compared with the combination of MO (hex) with the anionic polymer. Statistical analysis showed that MO (hex) obtained the highest removals of the parameters analysed in lower dosages and no significant increase in parameters removal was observed when the polymer dosage was increased. The efficacy of the coagulant +/- anionic polymer was optimal when 30mg L(-1) of MO (hex) was used as a coagulant and 0.1 mg L(-1) of the anionic polymer was used as a flocculant aid, decreasing the time sedimentation from 1 h to 15 min.

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