Regina de Pinho Keller

Assessment of water and seafood microbiology quality in a mangrove region in Vitória, Brazil

Mangroves are vital part of the local economy for some communities in the region of Vitória, Brazil. Oysters, mussels, and crabs, which are naturally abundant in the mangroves, are harvested and largely consumed in restaurants and by the population. In recent years, unusually high rates of annual gastroenteritis cases have been reported in the region suggesting an association between the consumption of contaminated shellfish and the development of gastrointestinal diseases. The objective of this study was to evaluate water samples and mussels collected in the mangrove region using bacterial indicator Escherichia coli and enteric viruses (adenovirus, rotavirus, and norovirus). Our results showed that the region of study is impacted by a continuous discharge of domestic sewage. Although E. coli was detected at low densities in water samples, mussels were shown to be 400 times more contaminated throughout the period of the study. Adenovirus and rotavirus genomes were detected by nested-polymerase chain reaction respectively in 76 and 88% of water samples and 100% of mussel samples. Norovirus was found in 4.8% of water samples and was not detected in the mussels. The screening of bivalves for the presence of health-significant enteric viruses can help in the prevention of outbreaks among shellfish consumers and contribute to improvement of the estuarine environment.

Harvesting Microalgal Biomass grown in Anaerobic Sewage Treatment Effluent by the Coagulation-Flocculation Method: Effect of pH

Harvesting is a critical step in microalgal biomass production process for many reasons. Among the existing techniques available for harvesting and dewatering microalgal biomass, recovery from aqueous medium by coagulation-flocculation has been the most economically viable process, althoughit is highly dependent on pH. This study aims to assess alternative coagulants compared to the standard coagulant aluminum sulfate for microalgal biomass recovery from anaerobic effluent of domestic sewage treatment. The effluent quality was also analyzed after biomass recovery. Coagulants represented by modified tannin, cationic starch and aluminum sulfate recovered more than 90% of algae biomass, at concentrations greater than 80 mg/L, in the pH range 7-10. Cationic starch promoted higher microalgal biomass recovery with a wider pH range. Powdered seeds of Moringa oleifera and Hibiscus esculentus(okra) gum promoted biomass removal of 50%, only in the acidic range of pH. After sedimentation of the microalgal biomass, the effluents showed a removal of >80% for phosphorus and nitrogen values and >50% for BOD and COD when using aluminum sulfate, cationic starch and modified tannin as coagulants. Natural organic coagulants in a wide pH range can replace aluminum sulfate, a reference coagulant in microalgal biomass recovery, without decreasing microalgal biomass harvesting efficiency and the quality of the final effluent.

Validação de método analítico livre de acetonitrila para análise de microcistinas por cromatografia líquida de alta eficiência

Blooms of cyanobacteria represent a public health risk due to their cyanotoxins such as microcystins. Liquid chromatography techniques to separate and quantify microcystins invariably use acetonitrile as the organic component of the mobile phase. The price and availability of acetonitrile together with its elevated toxicity encourage the validation of acetonitrile-free methods of microcystin analysis. In this work, methanol was employed as the organic solvent of the mobile phase and the validation method was performed with different environmental water samples. The method showed limits of detection between 0.17 and 0.25 µg/L and of quantification between 0.55 and 0.82 µg/L for the microcystin variants: -RR, -YR, -LR, -LA.

Use of polishing pond effluents to cultivate lettuce (Lactuca sativa) in a hydroponic system.

The sanitary quality and productivity of hydroponic lettuce (Lactuca sativa L.) plants cultivated under greenhouse conditions and treated with effluent from anaerobic reactor + polishing pond followed by physical-chemical treatment was evaluated. Two hydroponic cultivations were performed at summer and winter time at Vitoria-ES, Brazil. The treatments for both cultivations were: T1) conventional nutrient solution, T2) effluent from physical-chemical treatment, T3) effluent from polishing pond, and T4) effluent from polishing pond with 50% dilution. The plants were evaluated for microbial contamination, productivity and nutrient content. In all cases, no significant microbial contamination of lettuce was detected and the levels of macronutrients in the shoot system were similar to those in published reports. In the experiments from summer season, the treatments T1 and T2 resulted in higher production than the T3 and T4 treatments. Plants from T3 and T4 had a less developed root system as a result of reduced oxygenation from competition with the higher algae biomass content from the polishing pond effluent. In the winter season, the effect of the algal biomass was pronounced only in the T3 treatment (undiluted effluent from polishing pond). In conclusion, hydroponic cultivation of lettuce with pond effluent is suitable as a complement to water and nutrients for plants.

Isolamento e seleção de fungos produtores de lipases com base na atividade lipásica e no potencial hidrolítico sobre óleo comestível de soja e escuma de caixa de gordura

The use of fungal biomass as a lipase biocatalyst represents an attractive approach for the treatment of oil wastewater and production of biodiesel from oil and residual grease, due to its greater stability, possibility of reuse, and lower cost. In this work, a hundred filamentous fungi were isolated from grease trap and sewage scums, soil, and necrotized plants and insects tissues. The isolates were assessed for growth and lipase activity in the culture basic medium, for extracellular lipase activity, and mineral medium minimum + soybean oil + rhodamine, for intracellular lipase activity, with positive and differential response of 66 of them, including those belonging to the genera Aspergillus , Beauveria , Botrytis , Cladosporium , Colletotrichum , Fusarium , Geotrichum , Penicillium , Rhizomucor , and Verticillium . Following, previously selected Penicillium sp F002 and Rhizomucor sp. F018 isolates were evaluated in solid-state fermentation, for the hydrolytic potential on edible soybean oil and grease trap scum, quantified by: CO2 production, removal of the content of oils and greases, and biomass growth. Results confirmed the high extracellular lipase-activity of Penicillium sp. F002 and the high intracellular lipase activity of Rhizomucor sp. F018. Therefore, the isolated Rhizomucor sp. ECG18 showed potential for use in future research, in the form of whole-cell lipases, for oily wastewater treatment, and as a biocatalyst in the production of biodiesel from oil residues.