Aplicabilidade das equações isotermas de Freundlich e Langmuir na interação biossortiva de corantes têxteis com Saccharomyces cerevisiae liofilizada

This paper presents a study of the applicability of adsorption isotherms, known as Langmuir and Freundlich isotherm, between the biosorptive interaction of yeast lyophilized Saccharomyces cerevisiae and textile dyes. To that end, we prepared stock solutions of the textile dyes Direct Red 23 and Direct Red 75 in the concentration of 1.000μg/mL and a yeast suspension at 2,5%. We did experiments for two cases, firstly for the case that we have a fix concentration of yeast at 0,500mg/mL and an variable concentration of dye range from40, 50, 60, 80 and 100μg/mL, then for the case that we fixed the concentration of dye at 100μg/mL and the yeast concentration was variable range from 0,250, 0,500, 0,750, 1,000, 1,250mg/mL. For the dye Direct Red 23 we did analysis in the pH 2,5, 4,5 and 6,5; for the Direct Red 75, we just did for the pH 2,5. We leave the dye solution in contact with the yeast for 2 hours at a constant temperature of 30°C and then centrifuged and analyzed the sample in a spectrophotometer and finally made and analysis of parameters for the removal and study of the isotherms. After the biosorption, was observed that for the Direct Red 23 in the pH 2,5 was needed 1,407mg/mL of yeast for total removal, while for the pH 4,5 was needed 8,806mg/mL and in pH 6,5 was 9,286mg/mL; for the Direct Red 75 in pH 2,5 was needed 1,337mg/mL. This difference can be explain by the adsorption isotherms, was observed that in the case when the yeast was fix when we had in a acid pH the behavior of the system was compatible with the Langmuir isotherm, and thus, an monolayer pattern. And that when we decrease the acidity of the medium the system became more compatible with a Freundlich isotherm, and thus, a multilayer pattern; for the case that the yeast was variable this is not much evident, however for the pH 2,5 she became compatible with a Langmuir isotherm... (Complete abstract click electronic access below)

Avaliação do efeito do tratamento com surfactante químico e Pseudomonas aeruginosa LBI na toxicidade de solo contaminado com óleo lubrificante usado

Petroleum and its subproducts are considered a treat for the environmental quality because of the many environmental accidents that may occur during exploitation, transport and storage. A common remediation technique used in the contaminated areas is based on the use of surfactants, mainly the chemical ones, because they have low production costs. In the other hand, some microorganisms have indicate capacities of producing surfactants that emulsify substances and as result, offer a bigger contact surface for the microbiota degradation. This biossurfactants stand out in comparison with the chemical surfactants because they present lower micelar concentration values, are more tolerant for temperature and pH variation, because they are biodegradable, have low toxicity, higher emulsification and hydrocarbon solubilization index. In this way, after the surfactant application, a toxicity evaluation have to be made to identify the treatment effects. In soil, the activity of some microbial enzymes can show the environmental behavior of the contaminant under different treatment conditions. Dehydrogenase is one example of those enzymes that can demonstrate indirectly the effect of the pollutant on the soil microorganisms. The aim of this paper was to evaluate the toxicity after the addition of a surfactant and/or Pseudomonas aeruginosa LBI in soil contaminated by a mineral automotive lubricant. The previous mentioned bacteria are a potential biossurfactant (rhamnolipid) producer. In order to evaluate the toxicity, the dehydrogenase test was run. In this test, trifeniltetrazolium compound (TTC) after utilized as an electron acceptor, turns into trifenil formazan (TPF), that can be indirectly quantified using the absorbance measured by the spectrophotometer UV-visible. In this way, it was possible to quantify the dehydrogenase activity from the contaminated soil samples... (Complete abstract click electronic access below)

Descoloração e degradação de corantes têxteis por cianobactérias

The objective of the present work was to investigate the potential of cyanobacteria isolated from different environments in decolorizing eleven different types of textile dyes. For inoculum preparation 50 ml of BG-11 medium were used for the cyanobacteria Leptolyngbia CENA103, Leptolyngbia CENA104 and Phormidium autumnale UTEX1580 and 50 ml of SWBG-11 medium for Phormidium sp., Leptolyngbya sp. and Synecochoccus sp. Test tubes containing 10 ml of liquid medium and 0.02% of each dye (remazol, indigo blue, indanthrene blue RCL, drimaren blue CL-R, dispersol blue C-2R, drimaren red CL-5B, dispersol red C- 4G, indanthrene red FBB, drimaren yellow CL-R, palanil yellow 3G and indanthrene yellow 5GF) were inoculated with cyanobacteria. A spectrophotometer was used to verify the maximum absorbance of each dye and the percentage of decolorization and also thin layer chromatography (TLC). The results showed that all the tested cyanobacteria were capable to remove more than 50% of some dyes. The present study confirmed the capacity of cyanobacteria in decolorize and possibly degrade structurally different textile dyes, suggesting the possibility of their application in bioremediation studies. The data are promising, and will lead to further studies of dye degradation and its toxicicity.

Impacto geno e citotóxico em populações do caranguejo-uçá, Ucides cordatus (Linnaeus, 1763) (Crustacea, Brachyura, Ucididae), em manguezais do estado de São Paulo, Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Microencapsulação de óleo de palma por coacervação complexa em matrizes de gelatina/goma arábica e gelatina/alginato

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Study of the removal of chemical oxygen demand of the cheese whey and wastewater from dairy industry using Spirulina platensis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effectof inoculum in the emulsification index of biossufactants produced by Bacillus velezensis using wheat bran as substrate in solid-state fermentation

Conselho Nacional de Desenvolvimento em Pesquisa (CNPq)

Ethanol production by Zymomonas mobilis during sucrose fermentation: Optimization of culture conditions using factorial design

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of the pre-inoculum utilization in biosurfactant production by solid-state fermentation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cassava wastewater as carbon source for the polyhydroxybutyrate production by Azotobacter vinelandii CCT 2841

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Validação das unidades arbitrárias de teor de clorofilas obtido em folhas intactas de seringueira

The determination of foliar chlorophyll content is a characteristic that interests ecophysiologists and rural producers. With consideration for practical uses as well as scientific publications, our present work aims to establish equations, for rubber tree leaves, that can convert arbitrary units of expressing chlorophyll content to the international system. Chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chltot) were obtained from intact leaves using a portable chlorophyll detecting instrument. Leaves from different positions on the plant, at various stages of maturity, and representing a large spectrum of pigment concentrations, were collected and analyzed in the field using the Clorofil OG Falkner ® instrument, through four evaluations in forty-five medium leaflets. At the laboratory, leaflets underwent a process of pigment extraction. They were incubated in a water-bath with dimethylsulfoxide (DMSO), dosed in molecular absorption spectrophotometer, and converted into pigment content per unit of fresh weight using conventional equations. The data were evaluated according to the Pearson correlation coefficient and tested with different regression models. For all variables, the linear fit is the most adequate, with correlation coefficients (r) 0.74 for Chlb and 0.88 for Chla and Chltott.

Validação das unidades arbitrárias do teor de clorofilas obtido em folhas intactas de seringueira

The determination of foliar chlorophyll content is a characteristic that interests ecophysiologists and rural producers. With consideration for practical uses as well as scientific publications, our present work aims to establish equations, for rubber tree leaves, that can convert arbitrary units of expressing chlorophyll content to the international system. Chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chltot) were obtained from intact leaves using a portable chlorophyll detecting instrument. Leaves from different positions on the plant, at various stages of maturity, and representing a large spectrum of pigment concentrations, were collected and analyzed in the field using the Clorofil OG Falkner ® instrument, through four evaluations in forty-five medium leaflets. At the laboratory, leaflets underwent a process of pigment extraction. They were incubated in a water-bath with dimethylsulfoxide (DMSO), dosed in molecular absorption spectrophotometer, and converted into pigment content per unit of fresh weight using conventional equations. The data were evaluated according to the Pearson correlation coefficient and tested with different regression models. For all variables, the linear fit is the most adequate, with correlation coefficients (r) 0.74 for Chlb and 0.88 for Chla and Chltott .

Síntese e caracterização estrutural de pigmentos cerâmicos a base de cromita por método químico

The ceramic pigments are colored inorganic substances that during the process of dispersion in the ceramic glazes and subsequent calcination, are stable against physical and chemical attack. Therefore, they are crystalline compounds applied in the ceramic industry for coloring vitreous base. In this study, the Pechini method was used for obtaining the pigment CuCr2O4 with heat treatment at the temperatures of 800, 900 and 1000 ° C. The powder pigments were characterized on their structural, morphological and colorimetric aspects. The thermal analysis conducted on an amorphous precursor in a TG / DTA indicates the weight loss in the entire temperature range investigated, with characteristic exothermic peak of the elimination of the organic composition of the precursor around 300°C. The development of the crystalline phases were investigated by XRD, using a diffractometer with Cu Ka radiation and graphite monochromator, where it was observed the presence of crystalline phases corresponding to Cr2O3 and CuCr2O4.The measurements of the specific surface area of the powders pigments were carried out in an equipment Micromeritcs, model ASAP 2000, using N2 as gas of adsorption/desorption. The colorimetric measurements of the pigments were made in a colorimeter Gretac Macbeth Color-eye spectrophotometer 2180 / 2180UV in CIELAB standards. Based on the obtained results, it can be verified the thermal stability of the powder pigments of green coloration, which enables it as an alternative to the materials currently used in the manufacture of ceramic tiles.

Determination of heavy metals and genotoxicity of water from an artesian well in the city of Vazante- MG, Brazil

The city of Vazante-MG is of great socioeconomic and environmental interest because it is the most important zinc producer district of Brazil. The mineral processing and geochemical processes may determine high concentrations of heavy metals in water intended for human consumption. Thus, the present study aimed to quantify and evaluate the heavy metal genotoxicity of artesian water in the city by Atomic absorption spectrophotometer analysis and testing with the Allium cepa test, respectively. This study reveals a chemical contamination in well water in the city, caused by the presence of heavy metals. Therefore, it can be considered that the high levels of heavy metals found in water samples are correlated with the genotoxic events observed in root cells of A. cepa.

High activity photocatalyst powder formed by three ceramic oxides

A Photocatalyst ceramic powder that presented high photoactivity based on TiO2 modified with 25% molar of SnO2 and up to 5% molar of Ag2O was obtained in the present work. The aforementioned ceramic powder was obtained using all commercial oxides as well as the oxides mixture technique. The powders were ground in high energy mill for one hour with subsequent thermal treatment at 400°C for four hours. They were, furthermore, characterized using surface area of around 6m2/g, where the X-Ray diffraction results provided evidence for the presence of anatase and rutile phases, known to be typical characteristics of both the TiO2 and SnO2 used. During the thermal treatment, Ag2O was reduced to metallic silver. The photodegradation rehearsals were carried out using a 0.01 mmol/L Rhodamine B solution in a 100mg/L photocatalyst suspension in a 500ml beaker, which was irradiated with 4W germicide Ultraviolet light of 254nm. In addition, samples were removed after duration of about 10 minutes to an hour, where they were analyzed thoroughly in UV-vis spectrophotometer. The analysis of the results indicated that for the compositions up to 2.5% molar of Ag2O, the photoactivity was found to be greater than that of Degussa P25 photocatalyst powder, and as such it was then used as a reference. Taking into account 90% degradation of Rhodamine B, a duration period of 11 minutes was obtained for the developed photocatalyst powder compared to the 38 minutes observed for the Degussa P25. FEG-SEM micrographies enabled the verification of the morphology as well as the interaction of the oxide particles with the metallic silver, which led us to propose a model for the increase in photoactivity observed in the photocatalyst powder under investigation.