Solange K. Sakata

Diversity of hydrocarbon-degrading Klebsiella strains isolated from hydrocarbon-contaminated estuaries.

Aims:  To investigate the diversity and the catabolic capacity of oil‐degrading Klebsiella strains isolated from hydrocarbon‐contaminated sediments in Santos–São Vicente estuary systems in Brazil.

Copper removal using a heavy-metal resistant microbial consortium in a fixed-bed reactor

A heavy-metal resistant bacterial consortium was obtained from a contaminated river in São Paulo, Brazil and utilized for the design of a fixed-bed column for the removal of copper. Prior to the design of the fixed-bed bioreactor, the copper removal capacity by the live consortium and the effects of copper in the consortium biofilm formation were investigated. The Langmuir model indicated that the sorption capacity of the consortium for copper was 450.0 mg/g dry cells. The biosorption of copper into the microbial biomass was attributed to carboxyl and hydroxyl groups present in the microbial biomass. The effect of copper in planktonic cells to form biofilm under copper rich conditions was investigated with confocal microscopy. The results revealed that biofilm formed after 72 h exposure to copper presented a reduced thickness by 57% when compared to the control; however 84% of the total cells were still alive. The fixed-bed bioreactor was set up by growing the consortium biofilm on granular activated carbon (GAC) and analyzed for copper removal. The biofilm-GAC (BGAC) column retained 45% of the copper mass present in the influent, as opposed to 17% in the control column that contained GAC only. These findings suggest that native microbial communities in sites contaminated with heavy metals can be immobilized in fixed-bed bioreactors and used to treat metal contaminated water.

Anodic methoxylation of cinnamate esters

Este trabalho descreve a oxidacao eletroquimica do 4-metoxi-cinamato de metila e de outros esteres metilicos do acido cinâmico di- e tri- metoxilado, em solucao metanolica neutra ou alcalina. Nos estudos eletroquimicos foram empregadas voltametria ciclica, bem como eletrolises preparativas a potencial ou corrente controlados, em celas de um ou dois compartimentos. A influencia de parâmetros tais como densidade de corrente, tipo de cela, material do eletrodo, solvente, concentracao do substrato e base foi investigada para o 4-metoxi-cinamato de metila. Os produtos observados foram resultantes de metoxilacoes nucleares e/ou na cadeia lateral, entretanto com o aumento do numero de metoxilas no anel aromatico foram observados principalmente produtos referentes a metoxilacao no anel aromatico. As estruturas dos produtos tambem dependem do tipo de procedimento empregado no seu isolamento.

Biostimulation of metal-resistant microbial consortium to remove zinc from contaminated environments

Understanding the diversity and metal removal ability of microorganisms associated to contaminated aquatic environments is essential to develop metal remediation technologies in engineered environments. This study investigates through 16S rRNA deep sequencing the composition of a biostimulated microbial consortium obtained from the polluted Tietê River in São Paulo, Brazil. The bacterial diversity of the biostimulated consortium obtained from the contaminated water and sediment was compared to the original sample. The results of the comparative sequencing analyses showed that the biostimulated consortium and the natural environment had γ-Proteobacteria, Firmicutes, and uncultured bacteria as the major classes of microorganisms. The consortium optimum zinc removal capacity, evaluated in batch experiments, was achieved at pH=5 with equilibrium contact time of 120min, and a higher Zn-biomass affinity (KF=1.81) than most pure cultures previously investigated. Analysis of the functional groups found in the consortium demonstrated that amine, carboxyl, hydroxyl, and phosphate groups present in the consortium cells were responsible for zinc uptake.

Supercapacitor Application of Powder Prepared Using the Hydrogenation Disproportionation Desorption and Recombination (HDDR) Process in Graphene Oxide

Graphene (G) has been attracted great interest for its excellent electrical properties. However, the large-scale production of graphene is presently unfeasible. Graphene oxide (GO) can be (partly) reduced to graphene-like sheets by removing the oxygen-containing groups with the recovery of a conjugated structure. It can be produced using inexpensive graphite as raw material by cost-effective chemical methods. Although hydrogen (mixed with argon) at high temperature (1100°C) has been employed to reduce GO powder, the hydrogenation disproportionation desorption and recombination (HDDR) process in particular was unreported for this purpose. In the present work, attempts of reducing GO powder using the HDDR process have been carried out and investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The experimental results of processing graphene oxide powder using unmixed hydrogen at moderate temperatures (about 850°C) and relatively low pressures (<2 bars) have been reported.

Differentiation between the like and unlike isomers of dimethyl 3,4-di(p-anisyl)adipate using ¹H NMR spectroscopy

Apresenta-se aqui a diferenciacao entre os isomeros like (igual) e unlike (diferente) do 3,4-di(p-anisil)adipato de dimetila, que foi efetuada pelo uso combinado de espectroscopia de RMN de 1H, simulacao espectral e Mecânica Molecular, correlacionados pelo uso da Equacao de Altona, uma versao generalizada da Equacao de Karplus.