Estudo da aclimatação de lodo ativado com efluente “in natura” da industria de pescado

O presente trabalho estudou a adaptação e a atividade do lodo biológico procedente de um reator UASB de uma estação de tratamento de efluentes de uma indústria de processamento de pescado, para remoção biológica de nitrogênio em um Reator Batelada Seqüencial instrumentado em escala de bancada. A adaptação consistiu em aumento seqüencial da carga aplicada nas razões volumétricas efluente in natura : efluente sintético de 1:3,33; 1:2,5; 1:2,0; sendo a concentração inicial de inóculo empregada de 20 g SSV/L. Durante este período foram acompanhadas as variações de DQO, nitrato e amônia, onde se obteve uma remoção de até 80% da carga orgânica do efluente e de até 97% da matéria nitrogenada. O experimento com diluição de 1:3,33 foi realizado com adição de 0,5 % de sal para avaliar o efeito da salinidade, o qual também é considerado na análise dos resultados obtidos

Yarrowia lipolytica : an industrial workhorse

Yarrowia lipolytica is one of the most extensively studied ‘‘non-conventional’’ yeasts, being a strictly aerobic microorganism capable of producing important metabolites and having an intense secretory activity, which justifies efforts to use it in industry (as a biocatalyst), in molecular biology and in genetics studies. Moreover, Y. lipolytica has been considered an adequate model for dimorphism studies in yeasts. Yarrowia lipolytica presents the ability to grow on Olive Mill Wastewater (OMW) as well as to degradate organic compounds, including aliphatic and aromatic hydrocarbons, often accompanied by biosurfactants production. One of the most important products secreted by this microorganism is lipase which can be exploited for several applications in the detergent, food, pharmaceutical, and environmental industries. In addition, Y. lipolytica is able to produce citric acid and aroma from a variety of carbon sources, including sugars, alkanes, plant oils, starch hydrolysates, ethanol, and glycerol. Thus, this chapter presents an overview of Yarrowia lipolytica features and its major biotechnological applications

Estudo da aclimatação da flora microbiana a concentrações crescentes de efluente “in natura” da indústria de pescado em reator batelada sequencial

O presente trabalho estudou a adaptação e a atividade do lodo biológico procedente de um reator UASB de uma estação de tratamento de efluentes de uma indústria de processamento de pescado, para remoção biológica de nitrogênio em um Reator Batelada Seqüencial. A adaptação consistiu em aumento seqüencial da carga aplicada nas razões volumétricas efluente in natura : efluente sintético de 1:3,33; 1:2,5; 1:2,0; sendo a concentração inicial de inóculo empregada de 20 g SSV/L. Durante este período foram acompanhadas as variações de DQO, nitrato e amônia, onde se obteve uma remoção de até 80% da carga orgânica do efluente e de até 97% da matéria nitrogenada. O experimento com diluição de 1:3,33 foi conduzido com adição de 0,5 % de sal (NaCl) para avaliar o efeito da salinidade, o qual também é considerado na análise dos resultados obtidos.The present work analyzes the adaptation and activity of a sludge belonging to a UASB reactor of the wastewater treatment unit from a fish processing industry, in a bench scale Sequencing Batch Reactor for biological nitrogen removal. The sludge adaptation was carried using an increasing sequence of the applied load from 1:3.33; 1:2.5; 1:2.0; regarding to volume of in natura wastewater : synthetic sewage. The initial inocullum concentration employed was 20 g VSS / L. During this period COD, nitrate and ammonia concentrations were followed and a removal about 80% of the organic matter and up to 97% of nitrogen could be achieved. An experiment employing the greater dilution (1:3.33) with 0.5% salt (as NaCl) was also carried to evaluate the salinity effect which is considered in the analysis of the results herein presented

Efeito do sal no desempenho de um reator batelada sequencial

Neste trabalho investigou-se o desempenho de um Reator Batelada Sequencial no tratamento de efluentes salinos (0,5 a 6,0%) utilizando uma estratégia de enchimento por pulsos simétricos. Verificou-se que com a estratégia adotada se obtiveram elevadas porcentagens de remoção de amónia (acima de 70%) evidenciando a elevada eficiência do reator batelada sequencial no processo de nitrificação. Contudo, para 0,5 e 1,0% de sal a remoção de amónia diminuiu indicando que a influência do choque de adição de sal é maior no início da etapa de aclimatação da biomassa. Apesar de ter sido observado um aumento da concentração de biomassa dentro do reator durante o período estudado, as porcentagens de remoção de DQO diminuíram com o aumento da concentração de sal no efluente, apontando um efeito inibitório do sal. A diminuição do IVL com o aumento da concentração de sal indica a sedimentação dos flocos menos compactos, enquanto que o aumento da turbidez demonstra uma maior quantidade de sólidos suspensos no efluente tratado.The work aims to evaluate a Sequencing Batch Reactor performance treating with saline wastewater (0,5 to 6,0%) employing a filling strategy with symmetric pulses. It was verified that the adopted operational strategy provides ammoniacal nitrogen removal rates over than 70%, demonstrating the high efficiency of this reactor in the nitrification process. Nevertheless, amonia removal rate lowered for 0,5 and 1,0% NaCl, indicating that the influence of salt addition is more significant in the early biomass acclimation stages. Although it was observed an increase in biomass concentration inside the reactor along the operation period, the removal indexes for COD diminishes with salt concentration increase, denoting somehow an inhibitory effect. Lower SVI were achieved with an increase in salt concentration leading to the settling of less compact sludge, while higher turbidity reveals na increase in the suspended solids in the treated effluent

<i>Schistosoma mansoni</i> cercariae experience influx of macromolecules during skin penetration

We have observed that when cercariae penetrate the skin of mice, there is influx into their tissues of Lucifer Yellow and certain labelled molecules of up to 20 kDa molecular weight. This observation was made using a variety of fluorescent membrane-impermeant compounds injected into the skin before the application of cercariae. This unexpected phenomenon was investigated further by transforming cercariae in vitro in the presence of the membrane-impermeant compounds and examining the distribution by microscopy. In schistosomula derived from this procedure, the nephridiopore and surface membrane were labelled while the pre- and post-acetabular glands were not labelled. The region associated with the oesophagus within the pharyngeal muscle clearly contained the fluorescent molecules, as did the region adjacent to the excretory tubules and the germinal mass. We used cercariae stained with carmine to aid identification of regions labelled with Lucifer Yellow. Although the mechanism of this influx is unclear, the observation is significant. From it, we can suggest an hypothesis that, during skin penetration, exposure of internal tissues of the parasite to external macromolecules represents a novel host-parasite interfac

Limit laws of entrance times for low complexity Cantor minimal systems

This paper is devoted to the study of limit laws of entrance times to cylinder sets for Cantor minimal systems of zero entropy using their representation by means of ordered Bratteli diagrams. We study in detail substitution subshifts and we prove these limit laws are piecewise linear functions. The same kind of results is obtained for classical low complexity systems given by non stationary ordered Bratteli diagrams

Study of saline wastewater influence on activated sludge flocs through automated image analysis

BACKGROUND: In activated sludge systems, sludge settling ability is considered a critical step in effluent quality and determinant of solid-liquid separation processes. However, few studies have reported the influence of saline wastewater on activated sludge. This work aims the evaluation of settling ability properties of microbial aggregates in a sequencing batch reactor treating saline wastewaters of up to 60 g L-1 NaCl, by image analysis procedures. RESULTS: It was found that the sludge volume index (SVI) decreased with salt content up to 20 g L-1, remaining somewhat stable above this value. Furthermore, it was found that between the first salt concentration (5 g L-1) and 20 g L-1 aggregates suffered a strong deflocculation phenomenon, leading to a heavy loss of aggregated biomass. Regarding SVI prediction ability, a good correlation coefficient of 0.991 between observed and predicted SVI values was attained. CONCLUSION: From this work the deflocculation of aggregated biomass with salt addition due to pinpoint floc formation, dispersed bacteria growth and protozoa absence could be established. With respect to SVI estimation, and despite the good correlation obtained, caution is advisable given the low number of SVI data points.Fundação para a Ciência e a Tecnologia (FCT)ALFA cooperation project BIEURAM III (European Commission)CNPq (Brazil

Analysis of the effects of hyperbaric gases on S. cerevisiae cell cycle through a morphological approach

The effects of hyperbaric gases on the cell cycle of Saccharomyces cerevisiae were studied in batch cultures under pressures between 0.1 and 0.6 MPa and different gas compositions (air, oxygen, nitrogen or carbon dioxide). Classification of S. cerevisiae cells based on their morphology stages was obtained using an automatic image analysis procedure. Information on the distribution of different sub-populations along the cell cycle is reported. A structured morphological model was developed and used to describe the measured data. The results herein reported demonstrate that the bud separation phase is the limiting step in cell duplication. Additionally, the influence of the environmental conditions, specially the oxygen partial pressure, on the START event is reported. Under anaerobic conditions, no significant influence of hyperbaric gases on the cell cycle was verified.CAPES/GRICES, CNPq (Brazil) Fundação para a Ciência e a Tecnologia (FCT

Saccharomyces cerevisiae morphology under hyperbaric gases

The effects of hyperbaric stress on the morphology of Saccharomyces cerevisiae were studied in batch cultures under pressures between 0.1 MPa and 0.6 MPa and different gas compositions (air, O2, N2, or CO2), covering aerobic and anaerobic conditions. A method using automatic image analysis for cell classification based on their morphology was applied to experimental data. Cell viability was assessed through the Methylene Blue staining method and the percentages of viable and non-viable cells were also estimated using digital image processing. The results show that the effect of pressure on cell activity strongly depends on the nature of the gas used for pressurization. While nitrogen and air to a maximum of 0.6 MPa of pressure were innocuous to yeast, oxygen and carbon dioxide pressure caused cell inactivation, which was confirmed by the reduction on the number of budding cells with time and also a decrease in the average cell size (0.6 MPa CO2). A model taking into account cell viability reveals the opposing effects between oxygen availability and the baric and oxidative stresses present on the system. It is shown that cell viability in general is not constant during the experiments but strongly depends on the environment

Determination and modeling of yeast viability under stress conditions

In this work the effect of the total pressure and the oxygen concentration in the gas phase on the growth and viability of Saccharomyces cerevisiae is studied. Cell viability was measured staining with methylene blue and assessed using digital image processing. A model that takes into account cell viability was developed and used for the correlation of the measured data. A dependence of the death rate, KD, with the total pressure and the oxygen concentration is proposed. Its behavior indicates that opposing effects between oxygen availability and baric and oxidative stresses are present on the system. It is shown that the proposed model can, with this extra parameter, successfully describe not only the traditional X-P-S evolution but also the ratio of viable cells with time.Brasil. Ministério da Educação. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Brasil. Ministério da Ciência e Tecnologia. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)