Photocatalytic and photoelectrochemical inactivation of Escherichia coli and Staphylococcus aureus

Water disinfection usually requires expensive chemicals or equipment. Chlorination is a common disinfection method, although it is not able to inactivate all pathogens. High concentrations of residual chlorine also cause an unpleasant taste and smell in drinking water. As an alternative, photocatalysis and photoelectrochemical treatment has a high disinfection potential in drinking water by using solid catalysts, such as titanium dioxide. Highly reactive hydroxyl radical generated during the process serves as the main oxidant, capable of inactivating a wide range of microorganisms. In this study, we proposed a novel comparison between Gram-positive and gram-negative microorganisms. An immobilized TiO2 film promoted higher efficiency in water disinfection processes. The treatment effectively inactivated Escherichia coli and Staphylococcus aureus bacterial microorganisms in a shorter period than other alternative methods.

Hypobromous acid, a powerful endogenous electrophile: Experimental and theoretical studies

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

Consumo de amido e proteína, excreção de oxalato e características da urina de gatos alimentados com ração seca

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

Isolamento e identificação das micobactérias em águas tratadas provenientes do sistema de abastecimento de Araraquara-SP

Water quality is very important for the health and the population welfare, and the public supply system must provide water quality and suffi cient quantity for the entire population. Water treatment stations, are the main way to obtain water quality. When this doesn’t occur, several problems can affect the population, in this case, using water with poor quality is a constant risk of emergence causing various diseases. The elimination of microorganisms in treated water reduces competition, encouraging the multiplication of chlorine resistant bacteria as Mycobacterium genus frequently isolated from treated and chlorinated water. Considering the lack of indication from examinations of mycobacteria routine laboratory for quality control of drinking water and other human uses, the objective was to verify the presence isolate and identify the environmental mycobacteria in the system water source surface of Araraquara - SP. We analyzed 40 water samples, distributed as follows: ten water gross collected at Station Water Treatment Plant (WTP), harvested after ten fi ltration; ten collected in the reservoir after chlorination and ten in the network distribution. Were recovered 43 isolates of mycobacteria. All isolates were subjected to PCR-PRA. The mycobacteria were identifi ed as M. lentifl avum, M. parafortuitum, M. genavense, M. gordonae, M. fortuitum, M. confl uent, M. duvalii, M. avium subspecies paratuberculosis and M. szulgai. With these results, was concluded that water is an important source of environmental mycobacteria probably related to several human diseases, suggesting the carrying out continuous monitoring of the microorganisms in the system drinking water.

Qualidade de água utilizada para consumo em escolas e creches no município de São Carlos - SP

We know the importance of treating water for human consumption because changes in the physicochemical and / or biological has been associated with various health problems, the quality of water intended for human consumption must meet potability standards established by governmental decree 518/2004. The aim of this study was to evaluate the quality of water supplied schools and daycare in the city of São Carlos - SP. We selected 31 schools and kindergartens, and at intervals of 3 months, two water samples taken at three different points - network, tank and fi lter - totaling 186 samples, with an interval of three months, to verify possible differences in sampling points and at different times. The samples were evaluated for the following parameters: presence of total coliform and fecal coliform / E. coli count of heterotrophic bacteria, determination of pH, fl uoride, free residual chlorine, turbidity and color. The largest number of samples outside the standard for coliform was coming from the fi lters and the network, heterotrophic bacteria in most samples was taken out of standard fi lters. In the physical-chemical analysis of samples as many non-standard pH occurred in the network, network, and fl uoride in the fi lter pair in the fi lter to free chlorine and turbidity in the reservoir. The parameter with a larger sample size was inadequate fl uoride. We need more attention to the conservation, cleaning and maintenance of building reservoirs and fi lters in schools and kindergartens of San Carlos, since the water was considered unfi t for consumption.

Caracterização de Filmes a-C:H:Cl e a-C:H:Si:Cl produzidos por deposição à vapor químico assistido por plasma (PECVD) e deposição e implantação iônica por imersão em plasma (PIIID)

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Isolamento de leveduras em indústria de refrigerante e avaliação da susceptibilidade à ação antimicrobiana dos agentes sanificantes de uso industrial

Pós-graduação em Microbiologia - IBILCE

Desenvolvimento de técnicas e avaliações de antimicrobianos visando a produção de etanol carburante

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação sazonal de alguns parâmetros indicadores da qualidade de água no reservatório da usina hidrelétrica de Ilha Solteira-SP, Brasil

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

Modeling the crystallographic structure of Ho(Ni,Co,Mn)O3±δ perovskite-type manganite

Crystallographic and microstructural properties of Ho(Ni,Co,Mn)O3± perovskite-type multiferroic material are reported. Samples were synthesized with a modified polymeric precursor method. The synchrotron X-ray powder diffraction (SXRPD) technique associated to Rietveld refinement method was used to perform structural characterization. The crystallographic structures, as well as microstructural properties, were studied to determine unit cell parameters and volume, angles and atomic positions, crystallite size and strain. X-ray energies below the absorption edges of the transition metals helped to determine the mean preferred atomic occupancy for the substituent atoms. Furthermore, analyzing the degree of distortion of the polyhedra centered at the transitions metal atoms led to understanding the structural model of the synthesized phase. X-ray photoelectron spectroscopy (XPS) was performed to evaluate the valence states of the elements, and the tolerance factor and oxygen content. The obtained results indicated a small decrease distortion in structure, close to the HoMnO3 basis compound. In addition, the substituent atoms showed the same distribution and, on average, preferentially occupied the center of the unit cell.

Influence of sanitization on the physico-chemical and microbiological quality of organic and conventional broccoli

The present study was carried out in order to evaluate the effect of chlorinated and ozonized water on the physico-chemical characteristics of broccoli, produced under organic and conventional cultivation procedures. Organic and conventional broccolis were subjected to two sanitation treatments, using chlorine and ozone, and were kept under cold storage for seven days. Analyses of pH, titrable acidity, soluble solids and weight loss were performed and the content of Cu, Mn and Zn was determined. In addition, the presence of pesticides was verified. The results show no influence of the cultivation method or the sanitation treatment on sample weight loss. Cultivation methods and sanitizing treatments affected broccoli pH, titratable acidity, and soluble solids during the evaluation period. No differences regarding the metal content on organic and conventional broccoli were observed. Furthermore, the presence of organochlorine compounds, nor other pesticides, was not detected both in organic and conventional vegetables.

Does the use of ozonized water influence the chemical characteristics of organic cabbage (Brassica oleracea var. capitata)?

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

Effect of natural antimicrobials on microbiological and sensorial quality of fresh-cut cantaloupe melon

The effect of different natural antimicrobials on the microbiological and sensorial quality of fresh-cut Cantaloupe melons stored up to 10 days at 5°C was examined. Pieces of melon were washed for 1 min at 5ºC in water (control), vanillin (1000 mg/L and 2000 mg/L) or cinnamic acid (148.16 mg/L and 296.32 mg/L). Other antimicrobial treatments consisted of packaging the pieces of melon with an antimicrobial pad which contained cinnamic acid (148.16 mg/L and 296.32 mg/L). After 10 days of storage, significant differences among antimicrobials treatments and water treatment were found. In water treatment, the psychrotroph load was 3.63 ± 0.09 log cfu g-1 meanwhile on all antimicrobial treatments the values ranged from 3.04 ±0.13 log cfu g-1 to 3.28±0.1 log cfu g-1. Mesophilic growth in the control treatment averaged 6.79±0.06 log cfu g-1 meanwhile on antimicrobial treatments the counts were from 5.15±0.01 log cfu g-1 to 5.30±0.03 log cfu g-1. Total coliform levels were 7.8±0.1 log cfu g-1 when melon was washed in water, followed by washing with cinnamon (296.32 mg/L) at 6.5 log cfu g-1 and for the rest of the treatments were around 5.5 log cfu g-1. The treatments did not display differences among mould and yeast growth after 10 days of storage. The sensorial quality decreased throughout storage. However, at the end of storage, the scores ranged between 6.5 and 7, above the minimum level for marketability (level 5). Sensorial panelist noted a ‘sweet’ taste when vanillin was used as sanitizer. In all antimicrobial treatments, no relation was found between a higher dose and a higher microbial reduction. So, vanillin at 1000 mg/L in water or cinnamic acid at 148.16 mg/L provided in water dip or as a pad inside the trays could be optimal natural sanitizers to substitute the use of chlorine in fresh-cut products as Cantaloupe melon.

Modificação química de amido de mandioca e aplicação em emulsão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desinfecção fotoeletrocatalítica de águas contaminadas com Candida Parapsilosis utilizando eletrodos de W/WO3 em tratamento fotoeletrocatalítico

Pós-graduação em Química - IQ