Authors:M. I. Yoshida, V. R. Silva, P. C. C. Pinto, S. S. Sant'Anna, M. C. Silva, and C. F. Carvalho
In the aluminum industries, there are several steps involved in processing since the extraction of bauxite to obtain the final product (Al). During the development of these, various steps generated wastes. One of them, from the electrostatic filter of the calcination step of the Bayer process is a very fine black powder, rich in alumina (Al2O3) that does not meet industry specifications, and it is discarded in the industry yard. Alumina is a noble material and has high commercial value. This black powder has great prospects for recovery, recycling, and future applications. Therefore, it is important to perform characterization of tailings and to do that we have used XRD, SEM, EDS, FTIR, Raman, and thermal analysis.
Authors:P.B. Silva, S. Garcia, C. Baldo, and M.A.P.C. Celligoi
Bacillus subtilis natto is a potential source of fructooligosaccharides (FOS), which can be obtained by fermentation and may stimulate the growth of beneficial microorganisms in the colon representing a strategy to manipulate the intestinal microbiota acting as a prebiotic compound. The present study focuses on the ability of Lactobacillus ssp. strains to utilize FOS as a sole energy source. The results showed that FOS was equally good as glucose to provide energy source. The highest prebiotic activity score was obtained with Lactobacillus plantarum ATCC 14917 grown on FOS (0.526), followed by Lactobacillus casei (LC-1) (0.222). The lowest score was for Lactobacillus paracasei ATCC 27092 (−0.051). The results suggests that specific combinations of probiotic (L. plantarum ATCC 14917 and L. casei (LC-1)) and prebiotic (FOS) could be used as synbiotics in dairy and other foods.
Authors:M. Flues, I. M. C. Camargo, P. S. C. Silva, and B. P. Mazzilli
The Figueira coal-fired power plant (CFPP) is among the Brazilian CFPP which presents higher uranium concentration. Gamma-ray
spectrometry was used to determine 238U, 226Ra, 210Pb, 232 Th and 40K contents in pulverized coal, furnace bottom ash and fly ash samples. The natural radionuclide concentrations in pulverized
coal ranged from 813 to 2609 Bq . kg-1 for U series and from 22 to 40 Bq . kg-1 for 232 Th. The fly ash fraction gave concentrations ranging from 1442 to 14641 Bq . kg-1, for uranium series. The same enrichment factor was observed for 238U, 226Ra and 232 Th. Only 210Pb and stable Pb presented a high enrichment factor for the last stage filter fly ash. The concentration of the uranium series
found in the ashes is close to the limit adopted by the Brazilian guideline (CNEN-NN-4.01).22 Therefore, it is advisable to evaluate the environmental impact of the installation.
Authors:P. S. C. Silva, B. P. Mazzilli, and D. I. T. Fávaro
Cubatão River is located in Santos Basin, São Paulo State, Brazil. This region is characterized by the occurrence of estuaries
and mangrove. Due to its location, near the coastal line, it is also an important industrial area, where phosphate fertilizer
plants, petrol refineries, and chemical and steel industries are present. Such human activities contribute to the enhancement
of elemental composition in sediments and, in some cases, also increase the radionuclide concentrations, the so called Technologically
Enhanced Natural Occurring Radioactive Materials (TENORM). The contamination of land and sediments by TENORM is of major concern.
The activity concentration of U and Th series radionuclides was determined in five sediment samples from Cubatão River. The
activity concentration ratio was also determined. Equilibrium was observed for the ratio 234U/238U. The activity ratios of Th/238U, 228Ra/226Ra and 210Pb/226Ra were higher than the unity. In the first two cases, the observed values are due to the higher activity of Th in the sediment
and in the last case are probably due to the atmospheric deposition of 210Pb.
Authors:P. S. C. Silva, B. P. Mazzilli, and D. I. T. Fávaro
In the last decades considerable attention has been given to technologically enhanced natural occurring radioactive material
(TENORM). Within this frame, of particular concern is the phosphate fertilizer industry, located in Cubatão, São Paulo State,
Southwest Brazil. This industry is responsible for the production of 69 million tons of phosphogypsum waste, which is stockpiled
in the surrounding environment. This waste concentrates radionuclides of the natural series originally present in the phosphate
rocks used as raw material. This study aims to evaluate the environmental impact of such activities in the sediments of the
estuarine system. Contents of natural radionuclides from thorium and uranium series were measured in sediments from Cubatão
estuarine system, using high-resolution gamma-spectrometry. U and Th were determined by instrumental neutron activation analysis
(INAA). It was observed that U and Th concentration is higher in the rivers close to the phosphogypsum piles, at least five
points were identified as being affected by anthropogenic factors.
Authors:A. Castro, C. Palhau, S. Cunha, S. Camarinha, J. Silva, and P. Teixeira
Staphylococcus aureus is considered a global community and health care pathogen responsible for staphylococcal food poisoning. The aim of this study was to characterize several isolates of S. aureus recovered from different food products concerning enterotoxin genes and other virulence factors including antimicrobial resistance. In 2009, a total of 78 coagulase-positive staphylococci from 1454 food samples were identified to species level; 73 were confirmed as S. aureus. Of the S. aureus isolates 5.5% were resistant to oxacillin, 52.0% showed resistance to erythromycin, and 45.2% to tetracycline. Multidrug resistance was observed in 33.3% of the isolates (resistance to three or more antibiotics of different classes). SCCmec types IV and V were detected among methicillin-resistant S. aureus (MRSA). One MRSA isolate was pvl positive. The 52.0% of food isolates were shown to be enterotoxigenic; egc (63.0%), secbov (44.7%) were the main detected SEs. tst gene was also detected in food isolates. The present work demonstrates the presence of virulent S. aureus collected in 2009 in foods.
Authors:D. I. T. Fávaro, S. R. Damatto, P. S. C. Silva, A. A. Riga, A. Y. Sakamoto, and B. P. Mazzilli
Pantanal, located in the central region of South America, is recognized as one of the world's largest freshwater wetlands.
In order to verify possible changes in this environment, a study was undertaken in Nhecolândia Pantanal, Mato Grosso do Sul
State, Brazil. Two sediment cores from the Salina do Meio pond (SM1 and SM2) and one core from a small flood land named Baía
(B5) were collected in 2001. The elements As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb,
Th, U, Yb, Zn and Zr were determined by instrumental neutron activation analysis (INAA). Cluster and factorial analysis were
applied to the chemical data. The sedimentation rate in the SM2 core was determined by 210Pb method and the mean value found was 0.61 cm . y-1. The results obtained in the present study showed that recent geochemical processes such as desorption, precipitation and
dissolution can contribute for the high water alkalinity and salinity in the saline ponds.
Authors:B. Ramos, V. Ferreira, T.R.S. Brandão, P. Teixeira, and C.L.M. Silva
Pediococcus pentosaceus DT016, a bacteriocin producing strain, was isolated from fresh lettuce. A protein with antilisterial activity (bacDT016), between 11 to 17 kDa, was identified and characterized as the bioactive substance from the LAB culture. Highest bacteriocin production was noted after 15 h of growth. Antibacterial activity was affected by some enzymes and detergents, as well as by temperatures equal or above 80 ºC. DT016 strain contains an 1110 bp DNA fragment with homology to pediocin AcH/PA-1.
Authors:Edjane F. B. Silva, Marcílio P. Ribeiro, Luzia P. F. C. Galvão, Valter J. Fernandes, and Antonio S. Araujo
Degradation of low density polyethylene (LDPE) was studied for the pure polymer and mixed with silicoaluminophosphate SAPO-11 catalyst. SAPO-11 was synthesized by hydrothermal method using di-isoprolpylamine as structure template, and characterized by XRD and SEM. From X-ray diffraction, it was observed that SAPO-11 was obtained with high crystallinity. Using the model-free kinetics, proposed by Vyazovkin, the activation energies were determined for the process of polymer degradation. It was found that the degradation process of 90% of LDPE mixed with SAPO-11 over a period of 1 h, occurred at a temperature of 378 °C, while for the pure LDPE, the temperature was increased to 434 °C in the same period of time and conversion, indicating that SAPO-11 was an effective catalyst for the degradation of LDPE. The activation energy for the degradation of pure LDPE was equivalent to 251 kJ mol−1. Also, when the SAPO-11 was mixed with the polymer, this value was decreased to 243 kJ mol−1.